feat(server): log metadata and storage backends at startup

- archive local-fs-storage-backend, sqlite-metadata-backend,
  storage-orphan-reconciliation, metadata-managed-jwt-secret, default-local-backends
- sync specs: storage-backends, metadata-backends, storage-reconciliation,
  app-secrets; update photos/share-links
- defaults reflected in specs: SQLite and local FS

.env.example

@@ -6,18 +6,31 @@ PG_PASSWORD=change_me
 PG_DATABASE=shared_album
 PG_SSLMODE=disable
 
-# S3 (Garage on s3.localnet)
+# Metadata backend: sqlite (default, embedded single instance) or postgres
+DB_BACKEND=sqlite
+# Path to the SQLite database file (used when DB_BACKEND=sqlite)
+SQLITE_PATH=./galo.db
+
+# S3 (Garage on s3.localnet) - internal storage, never exposed to clients
 S3_ENDPOINT=http://s3.localnet:3900
 S3_REGION=garage
 S3_ACCESS_KEY=GKchange_me
 S3_SECRET_KEY=change_me
 S3_BUCKET=galo-data
 S3_USE_PATH_STYLE=true
-S3_PUBLIC_URL=http://s3.localnet:3900/galo-data
-S3_PRESIGN_TTL=1h
 
-# Auth
-JWT_SECRET=change_me_long_random
+# Storage backend: fs (default, local filesystem) or s3 (S3-compatible/Garage).
+# Blobs are always delivered through the backend via /api/objects/<key>.
+STORAGE_BACKEND=fs
+# Root directory for object blobs (STORAGE_BACKEND=fs)
+FS_ROOT=./data
+# Signs object URLs; falls back to the metadata-layer secret when empty
+URL_SECRET=
+# Lifetime of signed object URLs
+OBJECT_URL_TTL=1h
+
+# Auth. The token signing secret is generated on first start and stored in the
+# metadata layer (app_settings); it is not configured here.
 JWT_ACCESS_TTL=15m
 JWT_REFRESH_TTL=720h
 
@@ -28,3 +41,8 @@ APP_BASE_URL=http://localhost:8080
 # SSE
 SSE_HEARTBEAT_INTERVAL=25s
 SSE_CLIENT_BUFFER=64
+
+# Background worker (variant generation + object GC)
+WORKER_INTERVAL=5s
+WORKER_BATCH=10
+WORKER_PENDING_TTL=10m

.gitignore

@@ -7,3 +7,8 @@ frontend/build/
 frontend/.svelte-kit/
 node_modules/
 *.log
+
+# Local data backends (defaults)
+galo.db
+galo.db-*
+data/

Makefile

@@ -1,4 +1,4 @@
-.PHONY: build frontend backend run migrate tidy test clean
+.PHONY: build frontend backend run migrate reconcile reconcile-delete tidy test clean
 
 frontend:
 	cd frontend && npm ci && npm run build
@@ -20,6 +20,15 @@ run: backend
 migrate:
 	cd backend && go run ./cmd/migrate
 
+# Reconcile object storage against the metadata journal (report only).
+reconcile:
+	cd backend && go run ./cmd/reconcile
+
+# Reconcile and delete orphaned blobs older than --min-age (default 1h).
+# Override the grace period when needed: make reconcile-delete MIN_AGE=1m
+reconcile-delete:
+	cd backend && go run ./cmd/reconcile --delete $(if $(MIN_AGE),--min-age $(MIN_AGE),)
+
 tidy:
 	cd backend && go mod tidy
 

README.md

@@ -30,8 +30,19 @@ cp .env.example .env
 ```
 
 Ключевые переменные: `PG_*`, `S3_*` (обязательны `UsePathStyle=true` и регион
-`garage`), `JWT_SECRET`, `JWT_ACCESS_TTL`, `JWT_REFRESH_TTL`, `HTTP_ADDR`,
-`SSE_HEARTBEAT_INTERVAL`, `SSE_CLIENT_BUFFER`.
+`garage`), `JWT_ACCESS_TTL`, `JWT_REFRESH_TTL`, `HTTP_ADDR`,
+`SSE_HEARTBEAT_INTERVAL`, `SSE_CLIENT_BUFFER`. Секрет подписи токенов не задаётся
+в окружении: он генерируется при первом старте и хранится в слое метаданных
+(`app_settings`).
+
+Слои данных выбираются параметрами (по умолчанию — локальный режим):
+
+- `STORAGE_BACKEND=fs|s3` — где лежат блобы: `fs` (по умолчанию, `FS_ROOT=./data`)
+  или `s3` (S3/Garage); наружу всегда отдаётся бэкенд (`/api/objects/<key>`).
+- `DB_BACKEND=sqlite|postgres` — где лежат метаданные: `sqlite` (по умолчанию,
+  `SQLITE_PATH=./galo.db`) или `postgres`. SQLite — встроенный режим без внешней БД,
+  **только для одного экземпляра приложения на файл** (без горизонтального
+  масштабирования).
 
 ## Сборка
 
@@ -94,6 +105,21 @@ TEST_DATABASE_URL='postgres://user:pass@pg.localnet:5432/galo?sslmode=disable' \
   cd backend && go test ./internal/repo/ -v
 ```
 
+## Реконсиляция хранилища
+
+Сборка мусора воркера управляется журналом `objects` и не сканирует хранилище, поэтому
+блобы без строки в журнале (после сброса БД в обход журнала и т.п.) накапливаются.
+Ручная сверка:
+
+```bash
+go run ./cmd/reconcile            # отчёт: сироты (есть в хранилище, нет в журнале) и пропавшие
+go run ./cmd/reconcile --delete   # удалить сироты старше --min-age (по умолчанию 1h)
+```
+
+- По умолчанию ничего не удаляется; удаление только по явному `--delete`.
+- Область — префикс `objects/`; блобы старого формата `albums/` не затрагиваются.
+- Пропавшие ключи (в журнале есть, в хранилище нет) только сообщаются.
+
 ## Деплой через systemd
 
 1. Соберите бинарник: `make build`.
@@ -129,11 +155,12 @@ backend/
   cmd/migrate/           # применение миграций
   internal/config        # чтение env
   internal/db            # pgx + golang-migrate
-  internal/storage       # S3 (Garage)
+  internal/storage       # S3 (Garage) / локальная ФС, отдача через бэкенд
+  internal/store         # фабрика репозиториев (postgres / sqlite)
   internal/auth          # JWT, bcrypt, refresh
   internal/albums        # альбомы
   internal/members       # участники, роли, инвайты
-  internal/photos        # загрузка, варианты, presigned URL
+  internal/photos        # загрузка, варианты, отдача через бэкенд
   internal/social        # лайки, комментарии
   internal/notifications # персональные уведомления
   internal/sharelinks    # ссылки для просмотра

backend/cmd/backfill-exif/main.go

@@ -9,8 +9,9 @@ import (
 
 	"shared-album/internal/config"
 	"shared-album/internal/db"
-	"shared-album/internal/photos"
+	"shared-album/internal/settings"
 	"shared-album/internal/storage"
+	"shared-album/internal/store"
 )
 
 func main() {
@@ -35,14 +36,20 @@ func main() {
 	}
 	defer pool.Close()
 
-	store, err := storage.New(ctx, cfg.S3)
+	repos := store.NewPostgres(pool)
+	secret, err := repos.Settings.Ensure(ctx, settings.JWTSecretKey, settings.GenerateSecret)
+	if err != nil {
+		slog.Error("secret init failed", "error", err)
+		os.Exit(1)
+	}
+
+	blob, err := storage.Open(ctx, cfg, secret)
 	if err != nil {
 		slog.Error("storage init failed", "error", err)
 		os.Exit(1)
 	}
 
-	photoStore := photos.NewStore(pool)
-	updated, err := photoStore.BackfillEXIF(ctx, store.Get)
+	updated, err := repos.Photos.BackfillEXIF(ctx, blob.Get)
 	if err != nil {
 		slog.Error("backfill failed", "error", err)
 		os.Exit(1)

backend/cmd/reconcile/main.go

@@ -0,0 +1,169 @@
+// Command reconcile compares the object storage with the metadata journal and
+// reports orphaned blobs (present in storage, absent from the journal). With
+// --delete it removes orphans older than --min-age. It never touches missing
+// keys (in the journal but not in storage) and never runs automatically.
+package main
+
+import (
+	"bufio"
+	"context"
+	"flag"
+	"io/fs"
+	"log/slog"
+	"os"
+	"strings"
+	"time"
+
+	assets "shared-album"
+	"shared-album/internal/config"
+	"shared-album/internal/db"
+	"shared-album/internal/reconcile"
+	"shared-album/internal/settings"
+	"shared-album/internal/storage"
+	"shared-album/internal/store"
+)
+
+const objectPrefix = "objects/"
+
+func main() {
+	loadDotEnv(".env")
+	loadDotEnv("../.env")
+
+	slog.SetDefault(slog.New(slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{Level: slog.LevelInfo})))
+
+	deleteFlag := flag.Bool("delete", false, "delete orphaned blobs older than --min-age")
+	minAge := flag.Duration("min-age", time.Hour, "minimum blob age before deletion is allowed")
+	sample := flag.Int("sample", 20, "number of example keys to print")
+	flag.Parse()
+
+	cfg, err := config.Load()
+	if err != nil {
+		slog.Error("config error", "error", err)
+		os.Exit(1)
+	}
+
+	ctx := context.Background()
+
+	repos, closer, err := openRepos(ctx, cfg)
+	if err != nil {
+		slog.Error("metadata open failed", "error", err)
+		os.Exit(1)
+	}
+	defer closer()
+
+	secret, err := repos.Settings.Ensure(ctx, settings.JWTSecretKey, settings.GenerateSecret)
+	if err != nil {
+		slog.Error("secret init failed", "error", err)
+		os.Exit(1)
+	}
+
+	blob, err := storage.Open(ctx, cfg, secret)
+	if err != nil {
+		slog.Error("storage init failed", "error", err)
+		os.Exit(1)
+	}
+
+	objects, err := blob.List(ctx, objectPrefix)
+	if err != nil {
+		slog.Error("list storage", "error", err)
+		os.Exit(1)
+	}
+	journaled, err := repos.Photos.AllStorageKeys(ctx)
+	if err != nil {
+		slog.Error("list journal", "error", err)
+		os.Exit(1)
+	}
+
+	res := reconcile.Classify(objects, journaled)
+	slog.Info("reconciliation report",
+		"storage", cfg.Storage.Backend,
+		"storage_objects", len(objects),
+		"journal_keys", len(journaled),
+		"orphans", len(res.Orphans),
+		"missing", len(res.Missing))
+	printSamples("orphan", res.Orphans, *sample)
+	printSamples("missing", res.Missing, *sample)
+
+	if !*deleteFlag {
+		slog.Info("dry run: nothing deleted (pass --delete to remove orphans)")
+		return
+	}
+
+	targets := reconcile.Deletable(objects, res, objectPrefix, *minAge, time.Now())
+	if len(targets) == 0 {
+		slog.Info("no orphaned blobs old enough to delete", "min_age", minAge.String())
+		return
+	}
+	if err := blob.Delete(ctx, targets...); err != nil {
+		slog.Error("delete orphans", "error", err)
+		os.Exit(1)
+	}
+	slog.Info("deleted orphaned blobs", "count", len(targets), "min_age", minAge.String())
+}
+
+// openRepos builds the metadata repositories for the configured backend.
+func openRepos(ctx context.Context, cfg *config.Config) (store.Repos, func(), error) {
+	if cfg.Database.Backend == "sqlite" {
+		migFS, err := fs.Sub(assets.Migrations, "migrations/sqlite")
+		if err != nil {
+			return store.Repos{}, nil, err
+		}
+		if err := db.MigrateSQLite(cfg.Database.SQLitePath, migFS); err != nil {
+			return store.Repos{}, nil, err
+		}
+		database, err := db.OpenSQLite(cfg.Database.SQLitePath)
+		if err != nil {
+			return store.Repos{}, nil, err
+		}
+		return store.NewSQLite(database), func() { _ = database.Close() }, nil
+	}
+
+	migFS, err := fs.Sub(assets.Migrations, "migrations")
+	if err != nil {
+		return store.Repos{}, nil, err
+	}
+	if err := db.Migrate(cfg.Postgres.DSN(), migFS); err != nil {
+		return store.Repos{}, nil, err
+	}
+	pool, err := db.Connect(ctx, cfg.Postgres.DSN())
+	if err != nil {
+		return store.Repos{}, nil, err
+	}
+	return store.NewPostgres(pool), pool.Close, nil
+}
+
+func printSamples(label string, keys []string, n int) {
+	if len(keys) == 0 {
+		return
+	}
+	if n > len(keys) {
+		n = len(keys)
+	}
+	for _, k := range keys[:n] {
+		slog.Info("sample", "kind", label, "key", k)
+	}
+}
+
+func loadDotEnv(path string) {
+	f, err := os.Open(path)
+	if err != nil {
+		return
+	}
+	defer f.Close()
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+		if line == "" || strings.HasPrefix(line, "#") {
+			continue
+		}
+		key, value, ok := strings.Cut(line, "=")
+		if !ok {
+			continue
+		}
+		key = strings.TrimSpace(key)
+		value = strings.TrimSpace(value)
+		if _, exists := os.LookupEnv(key); !exists {
+			_ = os.Setenv(key, value)
+		}
+	}
+}

backend/cmd/server/main.go

@@ -15,10 +15,13 @@ import (
 
 	assets "shared-album"
 	"shared-album/internal/app"
+	"shared-album/internal/auth"
 	"shared-album/internal/config"
 	"shared-album/internal/db"
+	"shared-album/internal/settings"
 	"shared-album/internal/sse"
 	"shared-album/internal/storage"
+	"shared-album/internal/store"
 )
 
 func main() {
@@ -34,9 +37,49 @@ func main() {
 		os.Exit(1)
 	}
 
+	switch cfg.Database.Backend {
+	case "sqlite":
+		slog.Info("metadata backend", "backend", "sqlite", "path", cfg.Database.SQLitePath)
+	default:
+		slog.Info("metadata backend", "backend", "postgres",
+			"host", cfg.Postgres.Host, "database", cfg.Postgres.Database)
+	}
+	switch cfg.Storage.Backend {
+	case "fs":
+		slog.Info("storage backend", "backend", "fs", "root", cfg.Storage.FSRoot)
+	default:
+		slog.Info("storage backend", "backend", "s3",
+			"endpoint", cfg.S3.Endpoint, "bucket", cfg.S3.Bucket)
+	}
+
 	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
 	defer stop()
 
+	var (
+		repos  store.Repos
+		ping   func(ctx context.Context) error
+		closer func()
+	)
+	switch cfg.Database.Backend {
+	case "sqlite":
+		migFS, err := fs.Sub(assets.Migrations, "migrations/sqlite")
+		if err != nil {
+			slog.Error("migrations fs", "error", err)
+			os.Exit(1)
+		}
+		if err := db.MigrateSQLite(cfg.Database.SQLitePath, migFS); err != nil {
+			slog.Error("migration failed", "error", err)
+			os.Exit(1)
+		}
+		database, err := db.OpenSQLite(cfg.Database.SQLitePath)
+		if err != nil {
+			slog.Error("database open failed", "error", err)
+			os.Exit(1)
+		}
+		repos = store.NewSQLite(database)
+		ping = database.PingContext
+		closer = func() { _ = database.Close() }
+	default:
 		migFS, err := fs.Sub(assets.Migrations, "migrations")
 		if err != nil {
 			slog.Error("migrations fs", "error", err)
@@ -46,28 +89,40 @@ func main() {
 			slog.Error("migration failed", "error", err)
 			os.Exit(1)
 		}
-	slog.Info("migrations applied")
-
 		pool, err := db.Connect(ctx, cfg.Postgres.DSN())
 		if err != nil {
 			slog.Error("database connect failed", "error", err)
 			os.Exit(1)
 		}
-	defer pool.Close()
+		repos = store.NewPostgres(pool)
+		ping = pool.Ping
+		closer = pool.Close
+	}
+	defer closer()
+	slog.Info("migrations applied", "db_backend", cfg.Database.Backend)
 
-	store, err := storage.New(ctx, cfg.S3)
+	secret, err := repos.Settings.Ensure(ctx, settings.JWTSecretKey, settings.GenerateSecret)
+	if err != nil {
+		slog.Error("secret init failed", "error", err)
+		os.Exit(1)
+	}
+	tm := auth.NewTokenManager(secret, cfg.Auth.AccessTTL, cfg.Auth.RefreshTTL)
+
+	blob, err := storage.Open(ctx, cfg, secret)
 	if err != nil {
 		slog.Error("storage init failed", "error", err)
 		os.Exit(1)
 	}
-	if err := store.EnsureBucket(ctx); err != nil {
+	if err := blob.EnsureBucket(ctx); err != nil {
 		slog.Warn("could not ensure bucket", "error", err)
 	} else {
-		slog.Info("storage bucket ready", "bucket", store.Bucket())
+		slog.Info("storage ready", "location", blob.Bucket())
 	}
 
 	hub := sse.NewHub(cfg.SSE.ClientBuffer)
-	server := app.New(cfg, pool, store, hub)
+	server := app.New(cfg, repos, ping, tm, blob, hub)
+
+	go server.StartWorker(ctx)
 
 	httpServer := &http.Server{
 		Addr:              cfg.Server.Addr,

backend/embed.go

@@ -7,7 +7,7 @@ import "embed"
 //go:embed all:static
 var Static embed.FS
 
-// Migrations holds the SQL migration files.
+// Migrations holds the SQL migration files for every supported backend.
 //
-//go:embed migrations/*.sql
+//go:embed migrations/*.sql migrations/sqlite/*.sql
 var Migrations embed.FS

backend/go.mod

@@ -17,6 +17,7 @@ require (
 	github.com/google/uuid v1.6.0
 	github.com/jackc/pgx/v5 v5.11.0
 	golang.org/x/crypto v0.58.0
+	modernc.org/sqlite v1.60.1
 )
 
 require (
@@ -39,6 +40,7 @@ require (
 	github.com/cloudwego/base64x v0.1.6 // indirect
 	github.com/dsoprea/go-logging v0.0.0-20200710184922-b02d349568dd // indirect
 	github.com/dsoprea/go-utility/v2 v2.0.0-20221003172846-a3e1774ef349 // indirect
+	github.com/dustin/go-humanize v1.0.1 // indirect
 	github.com/ebitengine/purego v0.10.1 // indirect
 	github.com/gabriel-vasile/mimetype v1.4.12 // indirect
 	github.com/gin-contrib/sse v1.1.0 // indirect
@@ -56,12 +58,14 @@ require (
 	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/klauspost/cpuid/v2 v2.3.0 // indirect
 	github.com/leodido/go-urn v1.4.0 // indirect
-	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/mattn/go-isatty v0.0.24 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
+	github.com/ncruces/go-strftime v1.0.0 // indirect
 	github.com/pelletier/go-toml/v2 v2.2.4 // indirect
 	github.com/quic-go/qpack v0.6.0 // indirect
 	github.com/quic-go/quic-go v0.59.0 // indirect
+	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
 	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
 	github.com/ugorji/go/codec v1.3.1 // indirect
 	go.mongodb.org/mongo-driver/v2 v2.5.0 // indirect
@@ -73,4 +77,7 @@ require (
 	golang.org/x/text v0.43.0 // indirect
 	google.golang.org/protobuf v1.36.11 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
+	modernc.org/libc v1.77.1 // indirect
+	modernc.org/mathutil v1.7.1 // indirect
+	modernc.org/memory v1.12.1 // indirect
 )

backend/go.sum

@@ -85,6 +85,8 @@ github.com/dsoprea/go-utility/v2 v2.0.0-20221003142440-7a1927d49d9d/go.mod h1:LV
 github.com/dsoprea/go-utility/v2 v2.0.0-20221003160719-7bc88537c05e/go.mod h1:VZ7cB0pTjm1ADBWhJUOHESu4ZYy9JN+ZPqjfiW09EPU=
 github.com/dsoprea/go-utility/v2 v2.0.0-20221003172846-a3e1774ef349 h1:DilThiXje0z+3UQ5YjYiSRRzVdtamFpvBQXKwMglWqw=
 github.com/dsoprea/go-utility/v2 v2.0.0-20221003172846-a3e1774ef349/go.mod h1:4GC5sXji84i/p+irqghpPFZBF8tRN/Q7+700G0/DLe8=
+github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
+github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
 github.com/ebitengine/purego v0.10.1 h1:dewVBCBT2GaMu1SrNTYxQhgQBethzfhiwvZiLGP/qyY=
 github.com/ebitengine/purego v0.10.1/go.mod h1:iIjxzd6CiRiOG0UyXP+V1+jWqUXVjPKLAI0mRfJZTmQ=
 github.com/felixge/httpsnoop v1.1.0 h1:3YtUj32ZZkqZtt3sZZsClsymw/QDuVfpNhoA31zeORc=
@@ -129,8 +131,12 @@ github.com/golang/geo v0.0.0-20210211234256-740aa86cb551/go.mod h1:QZ0nwyI2jOfgR
 github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
 github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
+github.com/google/pprof v0.0.0-20260802141513-ef3492d7dac3 h1:LMLX+LgTNWpfvCBdFebv6EsYotImrt/Ppc5cXIriCSo=
+github.com/google/pprof v0.0.0-20260802141513-ef3492d7dac3/go.mod h1:jl5iWTm0/hd5PjEYEOuwAJ57L/CibdZfrqZ5XA5GrCk=
 github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/hashicorp/golang-lru/v2 v2.0.7 h1:a+bsQ5rvGLjzHuww6tVxozPZFVghXaHOwFs4luLUK2k=
+github.com/hashicorp/golang-lru/v2 v2.0.7/go.mod h1:QeFd9opnmA6QUJc5vARoKUSoFhyfM2/ZepoAG6RGpeM=
 github.com/jackc/pgerrcode v0.0.0-20220416144525-469b46aa5efa h1:s+4MhCQ6YrzisK6hFJUX53drDT4UsSW3DEhKn0ifuHw=
 github.com/jackc/pgerrcode v0.0.0-20220416144525-469b46aa5efa/go.mod h1:a/s9Lp5W7n/DD0VrVoyJ00FbP2ytTPDVOivvn2bMlds=
 github.com/jackc/pgpassfile v1.0.0 h1:/6Hmqy13Ss2zCq62VdNG8tM1wchn8zjSGOBJ6icpsIM=
@@ -155,8 +161,8 @@ github.com/leodido/go-urn v1.4.0 h1:WT9HwE9SGECu3lg4d/dIA+jxlljEa1/ffXKmRjqdmIQ=
 github.com/leodido/go-urn v1.4.0/go.mod h1:bvxc+MVxLKB4z00jd1z+Dvzr47oO32F/QSNjSBOlFxI=
 github.com/lib/pq v1.10.9 h1:YXG7RB+JIjhP29X+OtkiDnYaXQwpS4JEWq7dtCCRUEw=
 github.com/lib/pq v1.10.9/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
-github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
-github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+github.com/mattn/go-isatty v0.0.24 h1:tGZZoVgT/KiqK1c8ocVLeDS8BSWMRd47J3Lbz7vsReI=
+github.com/mattn/go-isatty v0.0.24/go.mod h1:nMCL3Zebbrt45jsMDgnfIwz6ydEQApk5oEI3HqDio6A=
 github.com/moby/docker-image-spec v1.3.1 h1:jMKff3w6PgbfSa69GfNg+zN/XLhfXJGnEx3Nl2EsFP0=
 github.com/moby/docker-image-spec v1.3.1/go.mod h1:eKmb5VW8vQEh/BAr2yvVNvuiJuY6UIocYsFu/DxxRpo=
 github.com/moby/moby/api v1.54.2 h1:wiat9QAhnDQjA7wk1kh/TqHz2I1uUA7M7t9SAl/JNXg=
@@ -172,6 +178,8 @@ github.com/modern-go/reflect2 v1.0.2 h1:xBagoLtFs94CBntxluKeaWgTMpvLxC4ur3nMaC9G
 github.com/modern-go/reflect2 v1.0.2/go.mod h1:yWuevngMOJpCy52FWWMvUC8ws7m/LJsjYzDa0/r8luk=
 github.com/morikuni/aec v1.0.0 h1:nP9CBfwrvYnBRgY6qfDQkygYDmYwOilePFkwzv4dU8A=
 github.com/morikuni/aec v1.0.0/go.mod h1:BbKIizmSmc5MMPqRYbxO4ZU0S0+P200+tUnFx7PXmsc=
+github.com/ncruces/go-strftime v1.0.0 h1:HMFp8mLCTPp341M/ZnA4qaf7ZlsbTc+miZjCLOFAw7w=
+github.com/ncruces/go-strftime v1.0.0/go.mod h1:Fwc5htZGVVkseilnfgOVb9mKy6w1naJmn9CehxcKcls=
 github.com/opencontainers/go-digest v1.0.0 h1:apOUWs51W5PlhuyGyz9FCeeBIOUDA/6nW8Oi/yOhh5U=
 github.com/opencontainers/go-digest v1.0.0/go.mod h1:0JzlMkj0TRzQZfJkVvzbP0HBR3IKzErnv2BNG4W4MAM=
 github.com/opencontainers/image-spec v1.1.1 h1:y0fUlFfIZhPF1W537XOLg0/fcx6zcHCJwooC2xJA040=
@@ -187,6 +195,8 @@ github.com/quic-go/qpack v0.6.0 h1:g7W+BMYynC1LbYLSqRt8PBg5Tgwxn214ZZR34VIOjz8=
 github.com/quic-go/qpack v0.6.0/go.mod h1:lUpLKChi8njB4ty2bFLX2x4gzDqXwUpaO1DP9qMDZII=
 github.com/quic-go/quic-go v0.59.0 h1:OLJkp1Mlm/aS7dpKgTc6cnpynnD2Xg7C1pwL6vy/SAw=
 github.com/quic-go/quic-go v0.59.0/go.mod h1:upnsH4Ju1YkqpLXC305eW3yDZ4NfnNbmQRCMWS58IKU=
+github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec h1:W09IVJc94icq4NjY3clb7Lk8O1qJ8BdBEF8z0ibU0rE=
+github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
 github.com/rogpeppe/go-internal v1.10.0 h1:TMyTOH3F/DB16zRVcYyreMH6GnZZrwQVAoYjRBZyWFQ=
 github.com/rogpeppe/go-internal v1.10.0/go.mod h1:UQnix2H7Ngw/k4C5ijL5+65zddjncjaFoBhdsK/akog=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
@@ -226,6 +236,8 @@ golang.org/x/crypto v0.58.0 h1:COkYLr4k7nDI4r6QtMML2AfzeIswWHAJthLS6K/M/54=
 golang.org/x/crypto v0.58.0/go.mod h1:Xh+kl5A+M0gMiWDytH2Hhr5Z7WbNCpv/eB/EFgfSk+w=
 golang.org/x/image v0.0.0-20191009234506-e7c1f5e7dbb8 h1:hVwzHzIUGRjiF7EcUjqNxk3NCfkPxbDKRdnNE1Rpg0U=
 golang.org/x/image v0.0.0-20191009234506-e7c1f5e7dbb8/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
+golang.org/x/mod v0.41.0 h1:qJmnOUb4YB+FsEuM3HcWucdZASCPGhsX6uljO6pog0c=
+golang.org/x/mod v0.41.0/go.mod h1:Ek9pY8RKWXwsWvd3rQiHYtMqkjSUV+s1Rj7j4H5Ur6o=
 golang.org/x/net v0.0.0-20191209160850-c0dbc17a3553/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20200320220750-118fecf932d8/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20200501053045-e0ff5e5a1de5/go.mod h1:qpuaurCH72eLCgpAm/N6yyVIVM9cpaDIP3A8BGJEC5A=
@@ -241,7 +253,6 @@ golang.org/x/sys v0.0.0-20210320140829-1e4c9ba3b0c4/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220728004956-3c1f35247d10/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220928140112-f11e5e49a4ec/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.49.0 h1:XbzkgYJHdqh/8m2Uu0W/dQv8nktxx4BFHp1M0gROTXA=
 golang.org/x/sys v0.49.0/go.mod h1:hNLxWAXmnKAxqDtdwIYC4bM9oQPEecfsnNMuSxOs3og=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
@@ -250,6 +261,8 @@ golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
 golang.org/x/text v0.43.0 h1:1QivrlhwAsnMOcqgOdl9my7s9OyZl8O5/UGUTJVXoWc=
 golang.org/x/text v0.43.0/go.mod h1:hbSIYA/amXcRXTFSZqh8tWHEoqRvvbKPJ2uz/KU+a+s=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.51.0 h1:k4Xc/1Om9jwkBJBo4NVLMSARBoWtK10mx+W5BnXCeAI=
+golang.org/x/tools v0.51.0/go.mod h1:9eEncMayCV6zRMGhR5eZEC2iBx98qWcF1HZ9Z7wJOoA=
 google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
 google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
@@ -262,3 +275,31 @@ gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+modernc.org/cc/v4 v4.29.7 h1:q+NXGJ0bK3b4TXFYQQVr9pYETGnmwFWkrUzJnMya/Tg=
+modernc.org/cc/v4 v4.29.7/go.mod h1:OnovgIhbbMXMu1aISnJ0wvVD1KnW+cAUJkIrAWh+kVI=
+modernc.org/ccgo/v4 v4.36.1 h1:ZNIUZAryN0UgnJwtyxrdEzcFc3yD4Cu4AzjfPXsLsIE=
+modernc.org/ccgo/v4 v4.36.1/go.mod h1:rrtGc2QkS239nYb/mQNuBMyjq3/y3ZXWbBjPoV3wqzA=
+modernc.org/fileutil v1.4.0 h1:j6ZzNTftVS054gi281TyLjHPp6CPHr2KCxEXjEbD6SM=
+modernc.org/fileutil v1.4.0/go.mod h1:EqdKFDxiByqxLk8ozOxObDSfcVOv/54xDs/DUHdvCUU=
+modernc.org/gc/v2 v2.6.5 h1:nyqdV8q46KvTpZlsw66kWqwXRHdjIlJOhG6kxiV/9xI=
+modernc.org/gc/v2 v2.6.5/go.mod h1:YgIahr1ypgfe7chRuJi2gD7DBQiKSLMPgBQe9oIiito=
+modernc.org/gc/v3 v3.1.5 h1:21ldfPfRYE31Tb7B3mwAK8gy1AxP4+dKjrOQPfqakoc=
+modernc.org/gc/v3 v3.1.5/go.mod h1:HFK/6AGESC7Ex+EZJhJ2Gni6cTaYpSMmU/cT9RmlfYY=
+modernc.org/goabi0 v0.2.0 h1:HvEowk7LxcPd0eq6mVOAEMai46V+i7Jrj13t4AzuNks=
+modernc.org/goabi0 v0.2.0/go.mod h1:CEFRnnJhKvWT1c1JTI3Avm+tgOWbkOu5oPA8eH8LnMI=
+modernc.org/libc v1.77.1 h1:Ct8j47QtiZ1Enj2DtFXQtUqrPCAjdCmPjtCuvrYQ0Hs=
+modernc.org/libc v1.77.1/go.mod h1:87/pZ4L6nD1zqW4nItuS12YO7hN1igAah34xjnQo/W0=
+modernc.org/mathutil v1.7.1 h1:GCZVGXdaN8gTqB1Mf/usp1Y/hSqgI2vAGGP4jZMCxOU=
+modernc.org/mathutil v1.7.1/go.mod h1:4p5IwJITfppl0G4sUEDtCr4DthTaT47/N3aT6MhfgJg=
+modernc.org/memory v1.12.1 h1:nFMiWrpStgZczNl6XI9GnIk/rWhYIyHGUaR04pGbp9g=
+modernc.org/memory v1.12.1/go.mod h1:/JP4VbVC+K5sU2wZi9bHoq2MAkCnrt2r98UGeSK7Mjw=
+modernc.org/opt v0.2.0 h1:tGyef5ApycA7FSEOMraay9SaTk5zmbx7Tu+cJs4QKZg=
+modernc.org/opt v0.2.0/go.mod h1:03fq9lsNfvkYSfxrfUhZCWPk1lm4cq4N+Bh//bEtgns=
+modernc.org/sortutil v1.2.1 h1:+xyoGf15mM3NMlPDnFqrteY07klSFxLElE2PVuWIJ7w=
+modernc.org/sortutil v1.2.1/go.mod h1:7ZI3a3REbai7gzCLcotuw9AC4VZVpYMjDzETGsSMqJE=
+modernc.org/sqlite v1.60.1 h1:/blz53O951KWFOso4QQvEs/Fq6cDBKLtMVrYNSeJVKw=
+modernc.org/sqlite v1.60.1/go.mod h1:1dIoEagfDE72QytD5scH1lxARtaUgKgHC/NuApA27r0=
+modernc.org/strutil v1.2.1 h1:UneZBkQA+DX2Rp35KcM69cSsNES9ly8mQWD71HKlOA0=
+modernc.org/strutil v1.2.1/go.mod h1:EHkiggD70koQxjVdSBM3JKM7k6L0FbGE5eymy9i3B9A=
+modernc.org/token v1.1.0 h1:Xl7Ap9dKaEs5kLoOQeQmPWevfnk/DM5qcLcYlA8ys6Y=
+modernc.org/token v1.1.0/go.mod h1:UGzOrNV1mAFSEB63lOFHIpNRUVMvYTc6yu1SMY/XTDM=

backend/internal/albums/repository.go

@@ -0,0 +1,18 @@
+package albums
+
+import (
+	"context"
+
+	"shared-album/internal/models"
+)
+
+// Repository is the persistence contract for the albums domain.
+type Repository interface {
+	Create(ctx context.Context, a *models.Album) error
+	OwnerID(ctx context.Context, id string) (string, error)
+	GetByID(ctx context.Context, id string) (*models.Album, error)
+	ListForUser(ctx context.Context, userID string) ([]models.Album, error)
+	Update(ctx context.Context, a *models.Album) error
+	Delete(ctx context.Context, id string) error
+	TrashPhotosByAlbum(ctx context.Context, albumID string) error
+}

backend/internal/albums/service.go

@@ -18,13 +18,13 @@ type MemberLookup interface {
 }
 
 type Service struct {
-	store   *Store
+	store   Repository
 	members MemberLookup
 	hub     *sse.Hub
-	storage *storage.Client
+	storage storage.Backend
 }
 
-func NewService(store *Store, members MemberLookup, hub *sse.Hub, storage *storage.Client) *Service {
+func NewService(store Repository, members MemberLookup, hub *sse.Hub, storage storage.Backend) *Service {
 	return &Service{store: store, members: members, hub: hub, storage: storage}
 }
 
@@ -61,12 +61,12 @@ func (s *Service) List(ctx context.Context, userID string) ([]models.Album, erro
 	return out, nil
 }
 
-// attachCover fills CoverThumbURL from the presigned thumbnail key, when present.
+// attachCover fills CoverThumbURL from the signed thumbnail URL, when present.
 func (s *Service) attachCover(ctx context.Context, a *models.Album) {
 	if s.storage == nil || a == nil || a.CoverThumbKey == "" {
 		return
 	}
-	if url, err := s.storage.PresignGet(ctx, a.CoverThumbKey); err == nil {
+	if url, err := s.storage.URL(ctx, a.CoverThumbKey); err == nil {
 		a.CoverThumbURL = url
 	}
 }

backend/internal/albums/sqlite_store.go

@@ -0,0 +1,142 @@
+package albums
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"time"
+
+	"shared-album/internal/models"
+	"shared-album/internal/sqliteutil"
+)
+
+// SQLiteStore is the SQLite implementation of Repository.
+type SQLiteStore struct {
+	db *sql.DB
+}
+
+func NewSQLiteStore(db *sql.DB) *SQLiteStore { return &SQLiteStore{db: db} }
+
+func (s *SQLiteStore) Create(ctx context.Context, a *models.Album) error {
+	var createdAt, updatedAt string
+	err := s.db.QueryRowContext(ctx,
+		`INSERT INTO albums (id, owner_id, title, description, cover_photo_id)
+		 VALUES ($1, $2, $3, $4, $5)
+		 RETURNING created_at, updated_at`,
+		a.ID, a.OwnerID, a.Title, a.Description, a.CoverPhotoID,
+	).Scan(&createdAt, &updatedAt)
+	if err != nil {
+		return err
+	}
+	a.CreatedAt = sqliteutil.ParseTime(createdAt)
+	a.UpdatedAt = sqliteutil.ParseTime(updatedAt)
+	return nil
+}
+
+func (s *SQLiteStore) OwnerID(ctx context.Context, id string) (string, error) {
+	var ownerID string
+	err := s.db.QueryRowContext(ctx, `SELECT owner_id FROM albums WHERE id = $1`, id).Scan(&ownerID)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return "", ErrNotFound
+		}
+		return "", err
+	}
+	return ownerID, nil
+}
+
+const sqliteAlbumColumns = `a.id, a.owner_id, a.title, a.description, a.cover_photo_id,
+	a.created_at, a.updated_at, COALESCE(co.storage_key, ''),
+	(SELECT count(*) FROM photos WHERE album_id = a.id),
+	(SELECT count(*) FROM album_members WHERE album_id = a.id)`
+
+const sqliteAlbumJoins = `
+	LEFT JOIN photo_objects cpo ON cpo.photo_id = a.cover_photo_id AND cpo.role = 'thumb'
+	LEFT JOIN objects co ON co.id = cpo.object_id`
+
+func scanSQLiteAlbum(scan func(...any) error) (*models.Album, error) {
+	var a models.Album
+	var cover sql.NullString
+	var createdAt, updatedAt string
+	if err := scan(&a.ID, &a.OwnerID, &a.Title, &a.Description, &cover, &createdAt, &updatedAt,
+		&a.CoverThumbKey, &a.PhotosCount, &a.MembersCount); err != nil {
+		return nil, err
+	}
+	if cover.Valid {
+		a.CoverPhotoID = &cover.String
+	}
+	a.CreatedAt = sqliteutil.ParseTime(createdAt)
+	a.UpdatedAt = sqliteutil.ParseTime(updatedAt)
+	return &a, nil
+}
+
+func (s *SQLiteStore) GetByID(ctx context.Context, id string) (*models.Album, error) {
+	row := s.db.QueryRowContext(ctx,
+		`SELECT `+sqliteAlbumColumns+` FROM albums a`+sqliteAlbumJoins+` WHERE a.id = $1`, id)
+	a, err := scanSQLiteAlbum(row.Scan)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, ErrNotFound
+		}
+		return nil, err
+	}
+	return a, nil
+}
+
+func (s *SQLiteStore) ListForUser(ctx context.Context, userID string) ([]models.Album, error) {
+	rows, err := s.db.QueryContext(ctx,
+		`SELECT `+sqliteAlbumColumns+` FROM albums a
+		 LEFT JOIN album_members m ON m.album_id = a.id AND m.user_id = $1`+sqliteAlbumJoins+`
+		 WHERE a.owner_id = $1 OR m.user_id IS NOT NULL
+		 ORDER BY a.created_at DESC`, userID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	out := []models.Album{}
+	for rows.Next() {
+		a, err := scanSQLiteAlbum(rows.Scan)
+		if err != nil {
+			return nil, err
+		}
+		out = append(out, *a)
+	}
+	return out, rows.Err()
+}
+
+func (s *SQLiteStore) Update(ctx context.Context, a *models.Album) error {
+	var updatedAt string
+	err := s.db.QueryRowContext(ctx,
+		`UPDATE albums
+		 SET title = $2, description = $3, cover_photo_id = $4, updated_at = $5
+		 WHERE id = $1
+		 RETURNING updated_at`,
+		a.ID, a.Title, a.Description, a.CoverPhotoID, sqliteutil.FormatTime(time.Now().UTC()),
+	).Scan(&updatedAt)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return ErrNotFound
+		}
+		return err
+	}
+	a.UpdatedAt = sqliteutil.ParseTime(updatedAt)
+	return nil
+}
+
+func (s *SQLiteStore) Delete(ctx context.Context, id string) error {
+	res, err := s.db.ExecContext(ctx, `DELETE FROM albums WHERE id = $1`, id)
+	if err != nil {
+		return err
+	}
+	if n, _ := res.RowsAffected(); n == 0 {
+		return ErrNotFound
+	}
+	return nil
+}
+
+func (s *SQLiteStore) TrashPhotosByAlbum(ctx context.Context, albumID string) error {
+	_, err := s.db.ExecContext(ctx,
+		`UPDATE photos SET deleted_at = $2 WHERE album_id = $1 AND deleted_at IS NULL`,
+		albumID, sqliteutil.FormatTime(time.Now().UTC()))
+	return err
+}

backend/internal/albums/store.go

@@ -44,11 +44,12 @@ func (s *Store) GetByID(ctx context.Context, id string) (*models.Album, error) {
 	var a models.Album
 	err := s.pool.QueryRow(ctx,
 		`SELECT a.id, a.owner_id, a.title, a.description, a.cover_photo_id, a.created_at, a.updated_at,
-		        COALESCE(p.thumb_key, ''),
+		        COALESCE(co.storage_key, ''),
 		        (SELECT count(*) FROM photos WHERE album_id = a.id),
 		        (SELECT count(*) FROM album_members WHERE album_id = a.id)
 		 FROM albums a
-		 LEFT JOIN photos p ON p.id = a.cover_photo_id
+		 LEFT JOIN photo_objects cpo ON cpo.photo_id = a.cover_photo_id AND cpo.role = 'thumb'
+		 LEFT JOIN objects co ON co.id = cpo.object_id
 		 WHERE a.id = $1`, id).
 		Scan(&a.ID, &a.OwnerID, &a.Title, &a.Description, &a.CoverPhotoID, &a.CreatedAt, &a.UpdatedAt, &a.CoverThumbKey, &a.PhotosCount, &a.MembersCount)
 	if err != nil {
@@ -63,12 +64,13 @@ func (s *Store) GetByID(ctx context.Context, id string) (*models.Album, error) {
 func (s *Store) ListForUser(ctx context.Context, userID string) ([]models.Album, error) {
 	rows, err := s.pool.Query(ctx,
 		`SELECT a.id, a.owner_id, a.title, a.description, a.cover_photo_id, a.created_at, a.updated_at,
-		        COALESCE(p.thumb_key, ''),
+		        COALESCE(co.storage_key, ''),
 		        (SELECT count(*) FROM photos WHERE album_id = a.id),
 		        (SELECT count(*) FROM album_members WHERE album_id = a.id)
 		 FROM albums a
 		 LEFT JOIN album_members m ON m.album_id = a.id AND m.user_id = $1
-		 LEFT JOIN photos p ON p.id = a.cover_photo_id
+		 LEFT JOIN photo_objects cpo ON cpo.photo_id = a.cover_photo_id AND cpo.role = 'thumb'
+		 LEFT JOIN objects co ON co.id = cpo.object_id
 		 WHERE a.owner_id = $1 OR m.user_id IS NOT NULL
 		 ORDER BY a.created_at DESC`, userID)
 	if err != nil {

backend/internal/app/app.go

@@ -1,13 +1,14 @@
 package app
 
 import (
+	"context"
+	"errors"
 	"io/fs"
 	"net/http"
 	"strings"
 	"time"
 
 	"github.com/gin-gonic/gin"
-	"github.com/jackc/pgx/v5/pgxpool"
 
 	assets "shared-album"
 	"shared-album/internal/albums"
@@ -21,15 +22,16 @@ import (
 	"shared-album/internal/social"
 	"shared-album/internal/sse"
 	"shared-album/internal/storage"
+	"shared-album/internal/store"
 )
 
 type Server struct {
 	cfg     *config.Config
-	pool    *pgxpool.Pool
-	storage *storage.Client
+	repos   store.Repos
+	ping    func(ctx context.Context) error
+	storage storage.Backend
 	hub     *sse.Hub
 
-	albumsStore *albums.Store
 	albums *albums.Service
 
 	auth *auth.Service
@@ -37,6 +39,7 @@ type Server struct {
 	membersSvc *members.Service
 
 	photos *photos.Service
+	worker *photos.Worker
 
 	social *social.Service
 
@@ -45,45 +48,47 @@ type Server struct {
 	share *sharelinks.Service
 }
 
-func New(cfg *config.Config, pool *pgxpool.Pool, st *storage.Client, hub *sse.Hub) *Server {
-	authStore := auth.NewStore(pool)
-	tm := auth.NewTokenManager(cfg.Auth.JWTSecret, cfg.Auth.AccessTTL, cfg.Auth.RefreshTTL)
-	authSvc := auth.NewService(authStore, tm)
+// New wires the domain services over the selected metadata repositories. ping
+// reports the health of the metadata backend so health stays backend-agnostic.
+func New(cfg *config.Config, repos store.Repos, ping func(ctx context.Context) error, tm *auth.TokenManager, st storage.Backend, hub *sse.Hub) *Server {
+	authSvc := auth.NewService(repos.Auth, tm)
 
-	albumsStore := albums.NewStore(pool)
-	membersStore := members.NewStore(pool)
+	notifSvc := notifications.NewService(repos.Notifications, hub)
 
-	notifStore := notifications.NewStore(pool)
-	notifSvc := notifications.NewService(notifStore, hub)
+	albumsSvc := albums.NewService(repos.Albums, repos.Members, hub, st)
+	membersSvc := members.NewService(repos.Members, repos.Albums, hub, notifSvc)
 
-	albumsSvc := albums.NewService(albumsStore, membersStore, hub, st)
-	membersSvc := members.NewService(membersStore, albumsStore, hub, notifSvc)
+	photosSvc := photos.NewService(repos.Photos, albumsSvc, st, hub)
+	photosWorker := photos.NewWorker(photosSvc, cfg.Worker.Interval, cfg.Worker.Batch, cfg.Worker.PendingTTL)
 
-	photosStore := photos.NewStore(pool)
-	photosSvc := photos.NewService(photosStore, albumsSvc, st, hub)
+	socialSvc := social.NewService(repos.Social, albumsSvc, repos.Photos, hub, notifSvc)
 
-	socialStore := social.NewStore(pool)
-	socialSvc := social.NewService(socialStore, albumsSvc, photosStore, hub, notifSvc)
-
-	shareStore := sharelinks.NewStore(pool)
-	shareSvc := sharelinks.NewService(shareStore, albumsSvc)
+	shareSvc := sharelinks.NewService(repos.ShareLinks, albumsSvc)
 
 	return &Server{
 		cfg:           cfg,
-		pool:          pool,
+		repos:         repos,
+		ping:          ping,
 		storage:       st,
 		hub:           hub,
-		albumsStore:   albumsStore,
 		albums:        albumsSvc,
 		auth:          authSvc,
 		membersSvc:    membersSvc,
 		photos:        photosSvc,
+		worker:        photosWorker,
 		social:        socialSvc,
 		notifications: notifSvc,
 		share:         shareSvc,
 	}
 }
 
+// StartWorker runs the background reconciler until ctx is cancelled.
+func (s *Server) StartWorker(ctx context.Context) {
+	if s.worker != nil {
+		s.worker.Run(ctx)
+	}
+}
+
 func (s *Server) Router() *gin.Engine {
 	r := gin.New()
 	r.Use(gin.Recovery())
@@ -98,6 +103,8 @@ func (s *Server) Router() *gin.Engine {
 
 	api := r.Group("/api")
 	api.GET("/health", s.health)
+	api.GET("/objects/*key", s.serveObject)
+	api.HEAD("/objects/*key", s.serveObject)
 
 	api.POST("/auth/register", authHandler.Register)
 	api.POST("/auth/login", authHandler.Login)
@@ -169,20 +176,40 @@ func (s *Server) Router() *gin.Engine {
 func (s *Server) health(c *gin.Context) {
 	ctx := c.Request.Context()
 	dbStatus := "ok"
-	if err := s.pool.Ping(ctx); err != nil {
+	if err := s.ping(ctx); err != nil {
 		dbStatus = "error"
 	}
-	s3Status := "ok"
+	storageLabel := s.cfg.Storage.Backend
+	if storageLabel == "" {
+		storageLabel = "s3"
+	}
+	storeStatus := "ok"
 	if err := s.storage.Ping(ctx); err != nil {
-		s3Status = "error"
+		storeStatus = "error"
 	}
 	status := http.StatusOK
 	overall := "ok"
-	if dbStatus != "ok" || s3Status != "ok" {
+	if dbStatus != "ok" || storeStatus != "ok" {
 		status = http.StatusServiceUnavailable
 		overall = "degraded"
 	}
-	c.JSON(status, gin.H{"status": overall, "db": dbStatus, "s3": s3Status})
+	c.JSON(status, gin.H{"status": overall, "db": dbStatus, storageLabel: storeStatus})
+}
+
+func (s *Server) serveObject(c *gin.Context) {
+	key := strings.TrimPrefix(c.Param("key"), "/")
+	switch err := s.storage.ServeObject(c.Writer, c.Request, key); {
+	case err == nil:
+		return
+	case errors.Is(err, storage.ErrSignedURLInvalid):
+		c.Status(http.StatusForbidden)
+	case errors.Is(err, storage.ErrObjectNotFound):
+		httpx.RespondError(c, httpx.NotFound("object_not_found", "object not found"))
+	case errors.Is(err, storage.ErrRangeNotSatisfiable):
+		c.Status(http.StatusRequestedRangeNotSatisfiable)
+	default:
+		c.Status(http.StatusInternalServerError)
+	}
 }
 
 func (s *Server) albumSSE(c *gin.Context) {
@@ -209,7 +236,7 @@ func (s *Server) shareAlbum(c *gin.Context) {
 		httpx.RespondError(c, err)
 		return
 	}
-	album, err := s.albumsStore.GetByID(c.Request.Context(), link.AlbumID)
+	album, err := s.repos.Albums.GetByID(c.Request.Context(), link.AlbumID)
 	if err != nil {
 		httpx.RespondError(c, httpx.NotFound("album_not_found", "album not found"))
 		return

backend/internal/app/health_test.go

@@ -0,0 +1,61 @@
+package app
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/gin-gonic/gin"
+
+	"shared-album/internal/config"
+	"shared-album/internal/storage"
+)
+
+func mustSigner(t *testing.T) *storage.Signer {
+	t.Helper()
+	signer, err := storage.NewSigner("http://app.test", "secret", time.Hour)
+	if err != nil {
+		t.Fatalf("signer: %v", err)
+	}
+	return signer
+}
+
+func TestHealthStorageLabel(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+	fs, err := storage.NewFS(t.TempDir(), mustSigner(t))
+	if err != nil {
+		t.Fatalf("fs: %v", err)
+	}
+	ok := func(context.Context) error { return nil }
+	srv := &Server{cfg: &config.Config{}, ping: ok, storage: fs}
+
+	call := func() map[string]any {
+		rec := httptest.NewRecorder()
+		c, _ := gin.CreateTestContext(rec)
+		c.Request = httptest.NewRequest(http.MethodGet, "/api/health", nil)
+		srv.health(c)
+		var body map[string]any
+		if err := json.Unmarshal(rec.Body.Bytes(), &body); err != nil {
+			t.Fatalf("decode: %v", err)
+		}
+		return body
+	}
+
+	srv.cfg.Storage.Backend = "fs"
+	if body := call(); body["fs"] != "ok" {
+		t.Fatalf("expected fs label ok, got %v", body)
+	}
+
+	srv.cfg.Storage.Backend = "s3"
+	if body := call(); body["s3"] != "ok" {
+		t.Fatalf("expected s3 label ok, got %v", body)
+	}
+
+	srv.cfg.Storage.Backend = ""
+	if body := call(); body["s3"] != "ok" {
+		t.Fatalf("expected default s3 label, got %v", body)
+	}
+}

backend/internal/app/objects_test.go

@@ -0,0 +1,114 @@
+package app
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"strconv"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/gin-gonic/gin"
+
+	"shared-album/internal/auth"
+	"shared-album/internal/config"
+	"shared-album/internal/sse"
+	"shared-album/internal/storage"
+	"shared-album/internal/store"
+)
+
+func newTestServerWithFS(t *testing.T) (*storage.FS, *gin.Engine) {
+	t.Helper()
+	gin.SetMode(gin.TestMode)
+	signer, err := storage.NewSigner("http://app.test", "secret", time.Hour)
+	if err != nil {
+		t.Fatalf("signer: %v", err)
+	}
+	fs, err := storage.NewFS(t.TempDir(), signer)
+	if err != nil {
+		t.Fatalf("new fs: %v", err)
+	}
+	noop := func(context.Context) error { return nil }
+	tm := auth.NewTokenManager("test-secret", 15*time.Minute, time.Hour)
+	srv := New(&config.Config{}, store.Repos{}, noop, tm, fs, sse.NewHub(1))
+	return fs, srv.Router()
+}
+
+func TestServeObjectRoute(t *testing.T) {
+	ctx := context.Background()
+	fs, r := newTestServerWithFS(t)
+	key := "objects/abc/original.jpg"
+	if err := fs.Put(ctx, key, strings.NewReader("0123456789"), 10, "image/jpeg"); err != nil {
+		t.Fatalf("put: %v", err)
+	}
+	raw, err := fs.URL(ctx, key)
+	if err != nil {
+		t.Fatalf("url: %v", err)
+	}
+	u, err := url.Parse(raw)
+	if err != nil {
+		t.Fatalf("parse: %v", err)
+	}
+
+	do := func(target string, rangeHeader string) *httptest.ResponseRecorder {
+		req := httptest.NewRequest(http.MethodGet, target, nil)
+		if rangeHeader != "" {
+			req.Header.Set("Range", rangeHeader)
+		}
+		rec := httptest.NewRecorder()
+		r.ServeHTTP(rec, req)
+		return rec
+	}
+
+	t.Run("valid", func(t *testing.T) {
+		rec := do(u.Path+"?"+u.RawQuery, "")
+		if rec.Code != http.StatusOK {
+			t.Fatalf("status = %d, want 200", rec.Code)
+		}
+		if rec.Body.String() != "0123456789" {
+			t.Fatalf("body = %q", rec.Body.String())
+		}
+	})
+
+	t.Run("range", func(t *testing.T) {
+		rec := do(u.Path+"?"+u.RawQuery, "bytes=2-5")
+		if rec.Code != http.StatusPartialContent {
+			t.Fatalf("status = %d, want 206", rec.Code)
+		}
+		if rec.Body.String() != "2345" {
+			t.Fatalf("body = %q, want 2345", rec.Body.String())
+		}
+	})
+
+	t.Run("expired", func(t *testing.T) {
+		q := u.Query()
+		q.Set("e", strconv.FormatInt(time.Now().Add(-time.Minute).Unix(), 10))
+		rec := do(u.Path+"?"+q.Encode(), "")
+		if rec.Code != http.StatusForbidden {
+			t.Fatalf("status = %d, want 403", rec.Code)
+		}
+	})
+
+	t.Run("forged", func(t *testing.T) {
+		q := u.Query()
+		q.Set("s", "deadbeef")
+		rec := do(u.Path+"?"+q.Encode(), "")
+		if rec.Code != http.StatusForbidden {
+			t.Fatalf("status = %d, want 403", rec.Code)
+		}
+	})
+
+	t.Run("missing", func(t *testing.T) {
+		raw, err := fs.URL(ctx, "objects/def/original.jpg")
+		if err != nil {
+			t.Fatalf("url: %v", err)
+		}
+		mu, _ := url.Parse(raw)
+		rec := do(mu.Path+"?"+mu.RawQuery, "")
+		if rec.Code != http.StatusNotFound {
+			t.Fatalf("status = %d, want 404", rec.Code)
+		}
+	})
+}

backend/internal/app/share_flow_test.go

@@ -0,0 +1,213 @@
+package app
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"image"
+	"image/color"
+	"image/png"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"os"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/jackc/pgx/v5/pgxpool"
+
+	"shared-album/internal/albums"
+	"shared-album/internal/auth"
+	"shared-album/internal/config"
+	"shared-album/internal/members"
+	"shared-album/internal/models"
+	"shared-album/internal/photos"
+	"shared-album/internal/sharelinks"
+	"shared-album/internal/sse"
+	"shared-album/internal/storage"
+	"shared-album/internal/store"
+)
+
+func integrationPool(t *testing.T) *pgxpool.Pool {
+	t.Helper()
+	dsn := os.Getenv("TEST_DATABASE_URL")
+	if dsn == "" {
+		t.Skip("TEST_DATABASE_URL not set")
+	}
+	pool, err := pgxpool.New(context.Background(), dsn)
+	if err != nil {
+		t.Skipf("cannot connect: %v", err)
+	}
+	if err := pool.Ping(context.Background()); err != nil {
+		t.Skipf("cannot ping: %v", err)
+	}
+	t.Cleanup(pool.Close)
+	return pool
+}
+
+func makeTestPNG(t *testing.T) []byte {
+	t.Helper()
+	img := image.NewRGBA(image.Rect(0, 0, 4, 4))
+	for x := 0; x < 4; x++ {
+		for y := 0; y < 4; y++ {
+			img.Set(x, y, color.RGBA{R: uint8(x * 40), G: uint8(y * 40), B: 128, A: 255})
+		}
+	}
+	var buf bytes.Buffer
+	if err := png.Encode(&buf, img); err != nil {
+		t.Fatalf("encode png: %v", err)
+	}
+	return buf.Bytes()
+}
+
+// runShareFlow uploads a photo and validates the read-only share flow returns a
+// usable photo URL. verify inspects/serves the URL according to the backend.
+func runShareFlow(t *testing.T, backend storage.Backend, verify func(t *testing.T, router *gin.Engine, raw string)) {
+	t.Helper()
+	ctx := context.Background()
+	pool := integrationPool(t)
+	gin.SetMode(gin.TestMode)
+
+	hub := sse.NewHub(1)
+	tm := auth.NewTokenManager("test-secret", 15*time.Minute, time.Hour)
+	srv := New(&config.Config{}, store.NewPostgres(pool), pool.Ping, tm, backend, hub)
+	router := srv.Router()
+
+	authStore := auth.NewStore(pool)
+	owner := &models.User{ID: auth.NewID(), Email: auth.NewID()[:8] + "@test.local", PasswordHash: "x", Name: "Owner"}
+	if err := authStore.CreateUser(ctx, owner); err != nil {
+		t.Fatalf("create user: %v", err)
+	}
+
+	albumsStore := albums.NewStore(pool)
+	albumsSvc := albums.NewService(albumsStore, members.NewStore(pool), hub, backend)
+	album, err := albumsSvc.Create(ctx, owner.ID, albums.CreateInput{Title: "Share Album"})
+	if err != nil {
+		t.Fatalf("create album: %v", err)
+	}
+
+	photosSvc := photos.NewService(photos.NewStore(pool), albumsSvc, backend, hub)
+	pngData := makeTestPNG(t)
+	if _, err := photosSvc.Upload(ctx, photos.UploadInput{
+		AlbumID: album.ID, UserID: owner.ID, Filename: "pic.png", Data: pngData,
+	}); err != nil {
+		t.Fatalf("upload: %v", err)
+	}
+
+	var keys []string
+	rows, err := pool.Query(ctx,
+		`SELECT o.storage_key FROM photo_objects po
+		 JOIN objects o ON o.id = po.object_id
+		 JOIN photos p ON p.id = po.photo_id
+		 WHERE p.album_id = $1`, album.ID)
+	if err == nil {
+		for rows.Next() {
+			var k string
+			if rows.Scan(&k) == nil {
+				keys = append(keys, k)
+			}
+		}
+		rows.Close()
+	}
+	t.Cleanup(func() {
+		_, _ = pool.Exec(ctx, `DELETE FROM photos WHERE album_id = $1`, album.ID)
+		for _, k := range keys {
+			_, _ = pool.Exec(ctx, `DELETE FROM objects WHERE storage_key = $1`, k)
+		}
+		_ = backend.Delete(context.Background(), keys...)
+		_, _ = pool.Exec(ctx, `DELETE FROM albums WHERE id = $1`, album.ID)
+		_, _ = pool.Exec(ctx, `DELETE FROM users WHERE id = $1`, owner.ID)
+	})
+
+	shareSvc := sharelinks.NewService(sharelinks.NewStore(pool), albumsSvc)
+	link, err := shareSvc.Create(ctx, album.ID, owner.ID, time.Hour)
+	if err != nil {
+		t.Fatalf("share create: %v", err)
+	}
+
+	rec := httptest.NewRecorder()
+	router.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/api/share/"+link.Token+"/photos", nil))
+	if rec.Code != http.StatusOK {
+		t.Fatalf("share photos status = %d body=%s", rec.Code, rec.Body.String())
+	}
+
+	var body struct {
+		Photos []models.Photo `json:"photos"`
+	}
+	if err := json.Unmarshal(rec.Body.Bytes(), &body); err != nil {
+		t.Fatalf("decode: %v", err)
+	}
+	if len(body.Photos) != 1 {
+		t.Fatalf("photos len = %d, want 1", len(body.Photos))
+	}
+	if body.Photos[0].OriginalURL == "" {
+		t.Fatalf("empty original url")
+	}
+	verify(t, router, body.Photos[0].OriginalURL)
+}
+
+func TestShareFlowWithFS(t *testing.T) {
+	signer, err := storage.NewSigner("http://app.test", "secret", time.Hour)
+	if err != nil {
+		t.Fatalf("signer: %v", err)
+	}
+	fs, err := storage.NewFS(t.TempDir(), signer)
+	if err != nil {
+		t.Fatalf("new fs: %v", err)
+	}
+	runShareFlow(t, fs, func(t *testing.T, router *gin.Engine, raw string) {
+		if !strings.Contains(raw, "/api/objects/") {
+			t.Fatalf("expected fs signed url, got %q", raw)
+		}
+		u, err := url.Parse(raw)
+		if err != nil {
+			t.Fatalf("parse url: %v", err)
+		}
+		rec := httptest.NewRecorder()
+		router.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, u.Path+"?"+u.RawQuery, nil))
+		if rec.Code != http.StatusOK {
+			t.Fatalf("fs object fetch status = %d", rec.Code)
+		}
+	})
+}
+
+func TestShareFlowWithS3(t *testing.T) {
+	endpoint := os.Getenv("S3_ENDPOINT")
+	if endpoint == "" {
+		t.Skip("S3_ENDPOINT not set")
+	}
+	signer, err := storage.NewSigner("http://app.test", "secret", time.Hour)
+	if err != nil {
+		t.Skipf("signer init: %v", err)
+	}
+	cl, err := storage.NewS3(context.Background(), config.S3{
+		Endpoint:     endpoint,
+		Region:       os.Getenv("S3_REGION"),
+		AccessKey:    os.Getenv("S3_ACCESS_KEY"),
+		SecretKey:    os.Getenv("S3_SECRET_KEY"),
+		Bucket:       os.Getenv("S3_BUCKET"),
+		UsePathStyle: true,
+	}, signer)
+	if err != nil {
+		t.Skipf("storage init: %v", err)
+	}
+	runShareFlow(t, cl, func(t *testing.T, router *gin.Engine, raw string) {
+		if !strings.Contains(raw, "/api/objects/") {
+			t.Fatalf("expected backend url, got %q", raw)
+		}
+		if strings.Contains(raw, "X-Amz-Signature") {
+			t.Fatalf("presigned url leaked to client: %q", raw)
+		}
+		u, err := url.Parse(raw)
+		if err != nil {
+			t.Fatalf("parse url: %v", err)
+		}
+		rec := httptest.NewRecorder()
+		router.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, u.Path+"?"+u.RawQuery, nil))
+		if rec.Code != http.StatusOK {
+			t.Fatalf("s3 object fetch status = %d", rec.Code)
+		}
+	})
+}

backend/internal/auth/repository.go

@@ -0,0 +1,19 @@
+package auth
+
+import (
+	"context"
+
+	"shared-album/internal/models"
+)
+
+// Repository is the persistence contract for the auth domain.
+type Repository interface {
+	CreateUser(ctx context.Context, u *models.User) error
+	GetUserByEmail(ctx context.Context, email string) (*models.User, error)
+	GetUserByID(ctx context.Context, id string) (*models.User, error)
+	UpdatePreferences(ctx context.Context, userID string, raw []byte) error
+	CreateRefreshToken(ctx context.Context, t *models.RefreshToken) error
+	GetRefreshToken(ctx context.Context, hash string) (*models.RefreshToken, error)
+	RevokeRefreshToken(ctx context.Context, id string) error
+	RevokeAllUserTokens(ctx context.Context, userID string) error
+}

backend/internal/auth/service.go

@@ -18,11 +18,11 @@ type TokenPair struct {
 }
 
 type Service struct {
-	store *Store
+	store Repository
 	tm    *TokenManager
 }
 
-func NewService(store *Store, tm *TokenManager) *Service {
+func NewService(store Repository, tm *TokenManager) *Service {
 	return &Service{store: store, tm: tm}
 }
 

backend/internal/auth/sqlite_store.go

@@ -0,0 +1,111 @@
+package auth
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"errors"
+	"time"
+
+	"shared-album/internal/models"
+	"shared-album/internal/sqliteutil"
+)
+
+// SQLiteStore is the SQLite implementation of Repository.
+type SQLiteStore struct {
+	db *sql.DB
+}
+
+func NewSQLiteStore(db *sql.DB) *SQLiteStore { return &SQLiteStore{db: db} }
+
+func (s *SQLiteStore) CreateUser(ctx context.Context, u *models.User) error {
+	_, err := s.db.ExecContext(ctx,
+		`INSERT INTO users (id, email, password_hash, name, avatar_url)
+		 VALUES ($1, $2, $3, $4, $5)`,
+		u.ID, u.Email, u.PasswordHash, u.Name, nullIfEmpty(u.AvatarURL))
+	return err
+}
+
+func (s *SQLiteStore) GetUserByEmail(ctx context.Context, email string) (*models.User, error) {
+	return s.scanUser(s.db.QueryRowContext(ctx,
+		`SELECT id, email, password_hash, name, COALESCE(avatar_url, ''),
+		        COALESCE(preferences, '{}'), created_at
+		 FROM users WHERE lower(email) = lower($1)`, email))
+}
+
+func (s *SQLiteStore) GetUserByID(ctx context.Context, id string) (*models.User, error) {
+	return s.scanUser(s.db.QueryRowContext(ctx,
+		`SELECT id, email, password_hash, name, COALESCE(avatar_url, ''),
+		        COALESCE(preferences, '{}'), created_at
+		 FROM users WHERE id = $1`, id))
+}
+
+func (s *SQLiteStore) scanUser(row *sql.Row) (*models.User, error) {
+	var u models.User
+	var prefs, createdAt string
+	if err := row.Scan(&u.ID, &u.Email, &u.PasswordHash, &u.Name, &u.AvatarURL, &prefs, &createdAt); err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, ErrNotFound
+		}
+		return nil, err
+	}
+	u.CreatedAt = sqliteutil.ParseTime(createdAt)
+	if prefs != "" && prefs != "null" {
+		_ = json.Unmarshal([]byte(prefs), &u.Preferences)
+	}
+	return &u, nil
+}
+
+func (s *SQLiteStore) UpdatePreferences(ctx context.Context, userID string, raw []byte) error {
+	res, err := s.db.ExecContext(ctx,
+		`UPDATE users SET preferences = $2 WHERE id = $1`, userID, string(raw))
+	if err != nil {
+		return err
+	}
+	if n, _ := res.RowsAffected(); n == 0 {
+		return ErrNotFound
+	}
+	return nil
+}
+
+func (s *SQLiteStore) CreateRefreshToken(ctx context.Context, t *models.RefreshToken) error {
+	_, err := s.db.ExecContext(ctx,
+		`INSERT INTO refresh_tokens (id, user_id, token_hash, expires_at)
+		 VALUES ($1, $2, $3, $4)`,
+		t.ID, t.UserID, t.TokenHash, sqliteutil.FormatTime(t.ExpiresAt))
+	return err
+}
+
+func (s *SQLiteStore) GetRefreshToken(ctx context.Context, hash string) (*models.RefreshToken, error) {
+	var t models.RefreshToken
+	var expiresAt, createdAt string
+	var revokedAt sql.NullString
+	err := s.db.QueryRowContext(ctx,
+		`SELECT id, user_id, token_hash, expires_at, revoked_at, created_at
+		 FROM refresh_tokens WHERE token_hash = $1`, hash).
+		Scan(&t.ID, &t.UserID, &t.TokenHash, &expiresAt, &revokedAt, &createdAt)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, ErrNotFound
+		}
+		return nil, err
+	}
+	t.ExpiresAt = sqliteutil.ParseTime(expiresAt)
+	t.CreatedAt = sqliteutil.ParseTime(createdAt)
+	t.RevokedAt = sqliteutil.ParseNullTime(revokedAt)
+	return &t, nil
+}
+
+func (s *SQLiteStore) RevokeRefreshToken(ctx context.Context, id string) error {
+	_, err := s.db.ExecContext(ctx,
+		`UPDATE refresh_tokens SET revoked_at = $2 WHERE id = $1 AND revoked_at IS NULL`,
+		id, sqliteutil.FormatTime(time.Now()))
+	return err
+}
+
+func (s *SQLiteStore) RevokeAllUserTokens(ctx context.Context, userID string) error {
+	_, err := s.db.ExecContext(ctx,
+		`UPDATE refresh_tokens SET revoked_at = $2 WHERE user_id = $1 AND revoked_at IS NULL`,
+		userID, sqliteutil.FormatTime(time.Now()))
+	return err
+}

backend/internal/config/config.go

@@ -28,12 +28,9 @@ type S3 struct {
 	SecretKey    string
 	Bucket       string
 	UsePathStyle bool
-	PublicURL    string
-	PresignTTL   time.Duration
 }
 
 type Auth struct {
-	JWTSecret  string
 	AccessTTL  time.Duration
 	RefreshTTL time.Duration
 }
@@ -48,12 +45,33 @@ type SSE struct {
 	ClientBuffer      int
 }
 
+type Worker struct {
+	Interval   time.Duration
+	Batch      int
+	PendingTTL time.Duration
+}
+
+type Storage struct {
+	Backend   string
+	FSRoot    string
+	URLSecret string
+	URLTTL    time.Duration
+}
+
+type Database struct {
+	Backend    string
+	SQLitePath string
+}
+
 type Config struct {
 	Postgres Postgres
 	S3       S3
+	Storage  Storage
+	Database Database
 	Auth     Auth
 	Server   Server
 	SSE      SSE
+	Worker   Worker
 }
 
 func Load() (*Config, error) {
@@ -72,9 +90,9 @@ func Load() (*Config, error) {
 		return nil, fmt.Errorf("invalid JWT_REFRESH_TTL: %w", err)
 	}
 
-	presignTTL, err := time.ParseDuration(getEnv("S3_PRESIGN_TTL", "1h"))
+	urlTTL, err := time.ParseDuration(getEnv("OBJECT_URL_TTL", "1h"))
 	if err != nil {
-		return nil, fmt.Errorf("invalid S3_PRESIGN_TTL: %w", err)
+		return nil, fmt.Errorf("invalid OBJECT_URL_TTL: %w", err)
 	}
 
 	heartbeat, err := time.ParseDuration(getEnv("SSE_HEARTBEAT_INTERVAL", "25s"))
@@ -92,6 +110,21 @@ func Load() (*Config, error) {
 		return nil, fmt.Errorf("invalid S3_USE_PATH_STYLE: %w", err)
 	}
 
+	workerInterval, err := time.ParseDuration(getEnv("WORKER_INTERVAL", "5s"))
+	if err != nil {
+		return nil, fmt.Errorf("invalid WORKER_INTERVAL: %w", err)
+	}
+
+	workerBatch, err := strconv.Atoi(getEnv("WORKER_BATCH", "10"))
+	if err != nil {
+		return nil, fmt.Errorf("invalid WORKER_BATCH: %w", err)
+	}
+
+	workerPendingTTL, err := time.ParseDuration(getEnv("WORKER_PENDING_TTL", "10m"))
+	if err != nil {
+		return nil, fmt.Errorf("invalid WORKER_PENDING_TTL: %w", err)
+	}
+
 	cfg := &Config{
 		Postgres: Postgres{
 			Host:     getEnv("PG_HOST", "pg.localnet"),
@@ -108,11 +141,18 @@ func Load() (*Config, error) {
 			SecretKey:    getEnv("S3_SECRET_KEY", ""),
 			Bucket:       getEnv("S3_BUCKET", "albums"),
 			UsePathStyle: pathStyle,
-			PublicURL:    getEnv("S3_PUBLIC_URL", ""),
-			PresignTTL:   presignTTL,
+		},
+		Storage: Storage{
+			Backend:   getEnv("STORAGE_BACKEND", "fs"),
+			FSRoot:    getEnv("FS_ROOT", "./data"),
+			URLSecret: getEnv("URL_SECRET", ""),
+			URLTTL:    urlTTL,
+		},
+		Database: Database{
+			Backend:    getEnv("DB_BACKEND", "sqlite"),
+			SQLitePath: getEnv("SQLITE_PATH", "./galo.db"),
 		},
 		Auth: Auth{
-			JWTSecret:  getEnv("JWT_SECRET", ""),
 			AccessTTL:  accessTTL,
 			RefreshTTL: refreshTTL,
 		},
@@ -124,14 +164,35 @@ func Load() (*Config, error) {
 			HeartbeatInterval: heartbeat,
 			ClientBuffer:      bufSize,
 		},
+		Worker: Worker{
+			Interval:   workerInterval,
+			Batch:      workerBatch,
+			PendingTTL: workerPendingTTL,
+		},
 	}
 
-	if cfg.Auth.JWTSecret == "" {
-		return nil, fmt.Errorf("JWT_SECRET is required")
-	}
+	switch cfg.Database.Backend {
+	case "postgres":
 		if cfg.Postgres.Password == "" {
 			return nil, fmt.Errorf("PG_PASSWORD is required")
 		}
+	case "sqlite":
+		if cfg.Database.SQLitePath == "" {
+			return nil, fmt.Errorf("SQLITE_PATH is required when DB_BACKEND=sqlite")
+		}
+	default:
+		return nil, fmt.Errorf("invalid DB_BACKEND %q (want postgres or sqlite)", cfg.Database.Backend)
+	}
+
+	switch cfg.Storage.Backend {
+	case "s3":
+	case "fs":
+		if cfg.Storage.FSRoot == "" {
+			return nil, fmt.Errorf("FS_ROOT is required when STORAGE_BACKEND=fs")
+		}
+	default:
+		return nil, fmt.Errorf("invalid STORAGE_BACKEND %q (want s3 or fs)", cfg.Storage.Backend)
+	}
 
 	return cfg, nil
 }

backend/internal/config/config_test.go

@@ -0,0 +1,134 @@
+package config
+
+import (
+	"testing"
+	"time"
+)
+
+func setRequiredEnv(t *testing.T) {
+	t.Helper()
+	t.Setenv("JWT_SECRET", "test-secret")
+	t.Setenv("PG_PASSWORD", "test-pass")
+}
+
+func TestLoadStorageBackend(t *testing.T) {
+	t.Run("defaults to fs", func(t *testing.T) {
+		setRequiredEnv(t)
+		t.Setenv("STORAGE_BACKEND", "")
+		cfg, err := Load()
+		if err != nil {
+			t.Fatalf("load: %v", err)
+		}
+		if cfg.Storage.Backend != "fs" || cfg.Storage.FSRoot != "./data" {
+			t.Fatalf("storage = %+v", cfg.Storage)
+		}
+	})
+
+	t.Run("fs with root", func(t *testing.T) {
+		setRequiredEnv(t)
+		t.Setenv("STORAGE_BACKEND", "fs")
+		t.Setenv("FS_ROOT", "/var/lib/galo/objects")
+		cfg, err := Load()
+		if err != nil {
+			t.Fatalf("load: %v", err)
+		}
+		if cfg.Storage.Backend != "fs" || cfg.Storage.FSRoot != "/var/lib/galo/objects" {
+			t.Fatalf("storage = %+v", cfg.Storage)
+		}
+	})
+
+	t.Run("fs empty root falls back to default", func(t *testing.T) {
+		setRequiredEnv(t)
+		t.Setenv("STORAGE_BACKEND", "fs")
+		t.Setenv("FS_ROOT", "")
+		t.Setenv("URL_SECRET", "")
+		cfg, err := Load()
+		if err != nil {
+			t.Fatalf("load: %v", err)
+		}
+		if cfg.Storage.FSRoot != "./data" {
+			t.Fatalf("FSRoot = %q, want ./data", cfg.Storage.FSRoot)
+		}
+	})
+
+	t.Run("invalid backend", func(t *testing.T) {
+		setRequiredEnv(t)
+		t.Setenv("STORAGE_BACKEND", "gcs")
+		if _, err := Load(); err == nil {
+			t.Fatal("expected error for invalid backend")
+		}
+	})
+
+	t.Run("object url ttl", func(t *testing.T) {
+		setRequiredEnv(t)
+		t.Setenv("STORAGE_BACKEND", "")
+		t.Setenv("OBJECT_URL_TTL", "30m")
+		cfg, err := Load()
+		if err != nil {
+			t.Fatalf("load: %v", err)
+		}
+		if cfg.Storage.URLTTL != 30*time.Minute {
+			t.Fatalf("URLTTL = %v, want 30m", cfg.Storage.URLTTL)
+		}
+	})
+}
+
+func TestLoadDatabaseBackend(t *testing.T) {
+	t.Run("defaults to sqlite", func(t *testing.T) {
+		setRequiredEnv(t)
+		t.Setenv("DB_BACKEND", "")
+		cfg, err := Load()
+		if err != nil {
+			t.Fatalf("load: %v", err)
+		}
+		if cfg.Database.Backend != "sqlite" || cfg.Database.SQLitePath != "./galo.db" {
+			t.Fatalf("database = %+v", cfg.Database)
+		}
+	})
+
+	t.Run("postgres requires password", func(t *testing.T) {
+		t.Setenv("JWT_SECRET", "s")
+		t.Setenv("PG_PASSWORD", "")
+		t.Setenv("DB_BACKEND", "postgres")
+		if _, err := Load(); err == nil {
+			t.Fatal("expected error for postgres without PG_PASSWORD")
+		}
+	})
+
+	t.Run("sqlite with path", func(t *testing.T) {
+		t.Setenv("JWT_SECRET", "s")
+		t.Setenv("PG_PASSWORD", "")
+		t.Setenv("DB_BACKEND", "sqlite")
+		t.Setenv("SQLITE_PATH", "/data/galo.db")
+		cfg, err := Load()
+		if err != nil {
+			t.Fatalf("load: %v", err)
+		}
+		if cfg.Database.Backend != "sqlite" || cfg.Database.SQLitePath != "/data/galo.db" {
+			t.Fatalf("database = %+v", cfg.Database)
+		}
+	})
+
+	t.Run("sqlite empty path falls back to default", func(t *testing.T) {
+		t.Setenv("JWT_SECRET", "s")
+		t.Setenv("PG_PASSWORD", "")
+		t.Setenv("DB_BACKEND", "sqlite")
+		t.Setenv("SQLITE_PATH", "")
+		cfg, err := Load()
+		if err != nil {
+			t.Fatalf("load: %v", err)
+		}
+		if cfg.Database.SQLitePath != "./galo.db" {
+			t.Fatalf("SQLitePath = %q, want ./galo.db", cfg.Database.SQLitePath)
+		}
+	})
+
+	t.Run("invalid backend", func(t *testing.T) {
+		t.Setenv("JWT_SECRET", "s")
+		t.Setenv("PG_PASSWORD", "p")
+		t.Setenv("DB_BACKEND", "mysql")
+		if _, err := Load(); err == nil {
+			t.Fatal("expected error for invalid backend")
+		}
+	})
+}

backend/internal/db/migrate.go

@@ -8,8 +8,10 @@ import (
 	"database/sql"
 	"github.com/golang-migrate/migrate/v4"
 	"github.com/golang-migrate/migrate/v4/database/pgx/v5"
+	sqlitemig "github.com/golang-migrate/migrate/v4/database/sqlite"
 	"github.com/golang-migrate/migrate/v4/source/iofs"
 	_ "github.com/jackc/pgx/v5/stdlib"
+	_ "modernc.org/sqlite"
 )
 
 // Migrate applies all up migrations from the given fs (root contains *.sql files).
@@ -39,3 +41,32 @@ func Migrate(dsn string, migrations fs.FS) error {
 	}
 	return nil
 }
+
+// MigrateSQLite applies all up migrations from the given fs to a SQLite database
+// at path (creating it if needed).
+func MigrateSQLite(path string, migrations fs.FS) error {
+	source, err := iofs.New(migrations, ".")
+	if err != nil {
+		return fmt.Errorf("migrations source: %w", err)
+	}
+
+	sqlDB, err := sql.Open("sqlite", path)
+	if err != nil {
+		return fmt.Errorf("open sql db: %w", err)
+	}
+	defer sqlDB.Close()
+
+	driver, err := sqlitemig.WithInstance(sqlDB, &sqlitemig.Config{})
+	if err != nil {
+		return fmt.Errorf("migrate driver: %w", err)
+	}
+
+	m, err := migrate.NewWithInstance("iofs", source, "sqlite", driver)
+	if err != nil {
+		return fmt.Errorf("migrate instance: %w", err)
+	}
+	if err := m.Up(); err != nil && !errors.Is(err, migrate.ErrNoChange) {
+		return fmt.Errorf("migrate up: %w", err)
+	}
+	return nil
+}

backend/internal/db/migrate_sqlite_test.go

@@ -0,0 +1,37 @@
+package db
+
+import (
+	"io/fs"
+	"path/filepath"
+	"testing"
+
+	assets "shared-album"
+)
+
+func TestMigrateSQLite(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "meta.db")
+	migFS, err := fs.Sub(assets.Migrations, "migrations/sqlite")
+	if err != nil {
+		t.Fatalf("migrations fs: %v", err)
+	}
+	if err := MigrateSQLite(path, migFS); err != nil {
+		t.Fatalf("migrate: %v", err)
+	}
+	if err := MigrateSQLite(path, migFS); err != nil {
+		t.Fatalf("migrate again: %v", err)
+	}
+
+	db, err := OpenSQLite(path)
+	if err != nil {
+		t.Fatalf("open: %v", err)
+	}
+	defer db.Close()
+
+	var n int
+	if err := db.QueryRow(`SELECT count(*) FROM sqlite_master WHERE type='table' AND name='objects'`).Scan(&n); err != nil {
+		t.Fatalf("query: %v", err)
+	}
+	if n != 1 {
+		t.Fatalf("objects table missing after migration")
+	}
+}

backend/internal/db/sqlite.go

@@ -0,0 +1,31 @@
+package db
+
+import (
+	"database/sql"
+	"fmt"
+	"strings"
+
+	_ "modernc.org/sqlite"
+)
+
+// OpenSQLite opens (creating if needed) a SQLite database tuned for a single
+// writer with concurrent readers: WAL journalling, a busy timeout so writers
+// wait instead of failing, and enforced foreign keys.
+func OpenSQLite(path string) (*sql.DB, error) {
+	if strings.TrimSpace(path) == "" {
+		return nil, fmt.Errorf("sqlite path is required")
+	}
+	dsn := fmt.Sprintf(
+		"file:%s?_pragma=journal_mode(WAL)&_pragma=busy_timeout(5000)&_pragma=foreign_keys(1)&_pragma=synchronous(NORMAL)&_txlock=immediate",
+		path,
+	)
+	db, err := sql.Open("sqlite", dsn)
+	if err != nil {
+		return nil, fmt.Errorf("open sqlite: %w", err)
+	}
+	if err := db.Ping(); err != nil {
+		_ = db.Close()
+		return nil, fmt.Errorf("ping sqlite: %w", err)
+	}
+	return db, nil
+}

backend/internal/db/sqlite_test.go

@@ -0,0 +1,45 @@
+package db
+
+import (
+	"context"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestOpenSQLite(t *testing.T) {
+	ctx := context.Background()
+	db, err := OpenSQLite(filepath.Join(t.TempDir(), "test.db"))
+	if err != nil {
+		t.Fatalf("open: %v", err)
+	}
+	defer db.Close()
+
+	if err := db.PingContext(ctx); err != nil {
+		t.Fatalf("ping: %v", err)
+	}
+
+	var mode string
+	if err := db.QueryRowContext(ctx, "PRAGMA journal_mode").Scan(&mode); err != nil {
+		t.Fatalf("journal_mode: %v", err)
+	}
+	if !strings.EqualFold(mode, "wal") {
+		t.Fatalf("journal_mode = %q, want wal", mode)
+	}
+
+	var fk int
+	if err := db.QueryRowContext(ctx, "PRAGMA foreign_keys").Scan(&fk); err != nil {
+		t.Fatalf("foreign_keys: %v", err)
+	}
+	if fk != 1 {
+		t.Fatalf("foreign_keys = %d, want 1", fk)
+	}
+
+	var busy int
+	if err := db.QueryRowContext(ctx, "PRAGMA busy_timeout").Scan(&busy); err != nil {
+		t.Fatalf("busy_timeout: %v", err)
+	}
+	if busy != 5000 {
+		t.Fatalf("busy_timeout = %d, want 5000", busy)
+	}
+}

backend/internal/e2e/sqlite_test.go

@@ -0,0 +1,198 @@
+package e2e
+
+import (
+	"bytes"
+	"context"
+	"database/sql"
+	"image"
+	"image/color"
+	"image/png"
+	"io/fs"
+	"path/filepath"
+	"testing"
+	"time"
+
+	assets "shared-album"
+	"shared-album/internal/albums"
+	"shared-album/internal/auth"
+	"shared-album/internal/db"
+	"shared-album/internal/photos"
+	"shared-album/internal/settings"
+	"shared-album/internal/sse"
+	"shared-album/internal/storage"
+	"shared-album/internal/store"
+)
+
+func makePNG(t *testing.T) []byte {
+	t.Helper()
+	img := image.NewRGBA(image.Rect(0, 0, 4, 4))
+	for x := 0; x < 4; x++ {
+		for y := 0; y < 4; y++ {
+			img.Set(x, y, color.RGBA{R: uint8(x * 40), G: uint8(y * 40), B: 128, A: 255})
+		}
+	}
+	var buf bytes.Buffer
+	if err := png.Encode(&buf, img); err != nil {
+		t.Fatalf("encode png: %v", err)
+	}
+	return buf.Bytes()
+}
+
+type stack struct {
+	db     *sql.DB
+	photos *photos.Service
+	albums *albums.Service
+	auth   *auth.Service
+}
+
+// openStack opens a migrated SQLite database at path and builds the services.
+func openStack(t *testing.T, path, blobRoot string) (*stack, func()) {
+	t.Helper()
+	migFS, err := fs.Sub(assets.Migrations, "migrations/sqlite")
+	if err != nil {
+		t.Fatalf("migrations fs: %v", err)
+	}
+	if err := db.MigrateSQLite(path, migFS); err != nil {
+		t.Fatalf("migrate: %v", err)
+	}
+	database, err := db.OpenSQLite(path)
+	if err != nil {
+		t.Fatalf("open: %v", err)
+	}
+	repos := store.NewSQLite(database)
+	hub := sse.NewHub(1)
+	signer, err := storage.NewSigner("http://app.test", "secret", time.Hour)
+	if err != nil {
+		t.Fatalf("signer: %v", err)
+	}
+	blob, err := storage.NewFS(blobRoot, signer)
+	if err != nil {
+		t.Fatalf("fs: %v", err)
+	}
+	authSvc := auth.NewService(repos.Auth, auth.NewTokenManager("secret", 15*time.Minute, time.Hour))
+	albumsSvc := albums.NewService(repos.Albums, repos.Members, hub, blob)
+	photosSvc := photos.NewService(repos.Photos, albumsSvc, blob, hub)
+	return &stack{db: database, photos: photosSvc, albums: albumsSvc, auth: authSvc}, func() { database.Close() }
+}
+
+func TestSQLiteEndToEndWithRestart(t *testing.T) {
+	ctx := context.Background()
+	path := filepath.Join(t.TempDir(), "galo.db")
+	blobs := t.TempDir()
+
+	st, closeDB := openStack(t, path, blobs)
+	worker := photos.NewWorker(st.photos, 20*time.Millisecond, 10, time.Minute)
+	wctx, cancel := context.WithCancel(ctx)
+	go worker.Run(wctx)
+
+	user, _, err := st.auth.Register(ctx, "e2e@test.local", "password123", "E2E")
+	if err != nil {
+		t.Fatalf("register: %v", err)
+	}
+	album, err := st.albums.Create(ctx, user.ID, albums.CreateInput{Title: "Trip"})
+	if err != nil {
+		t.Fatalf("create album: %v", err)
+	}
+	p, err := st.photos.Upload(ctx, photos.UploadInput{AlbumID: album.ID, UserID: user.ID, Filename: "a.png", Data: makePNG(t)})
+	if err != nil {
+		t.Fatalf("upload: %v", err)
+	}
+	waitFor(t, "variants of first photo", func() bool {
+		got, err := st.photos.Get(ctx, p.ID, user.ID)
+		return err == nil && got.ThumbURL != "" && got.PreviewURL != ""
+	})
+
+	if err := st.photos.PermanentDelete(ctx, p.ID, user.ID); err != nil {
+		t.Fatalf("permanent delete: %v", err)
+	}
+	waitFor(t, "garbage collection", func() bool {
+		var n int
+		return st.db.QueryRowContext(ctx, `SELECT count(*) FROM objects`).Scan(&n) == nil && n == 0
+	})
+
+	// Stop the worker, then queue another upload whose variant job must survive
+	// the restart and be processed by a fresh worker over the same file.
+	cancel()
+	time.Sleep(50 * time.Millisecond)
+
+	p2, err := st.photos.Upload(ctx, photos.UploadInput{AlbumID: album.ID, UserID: user.ID, Filename: "b.png", Data: makePNG(t)})
+	if err != nil {
+		t.Fatalf("upload p2: %v", err)
+	}
+	got2, _ := st.photos.Get(ctx, p2.ID, user.ID)
+	if got2.PreviewURL != "" {
+		t.Fatalf("variants generated before restart")
+	}
+	closeDB()
+
+	st2, close2 := openStack(t, path, blobs)
+	defer close2()
+	worker2 := photos.NewWorker(st2.photos, 20*time.Millisecond, 10, time.Minute)
+	wctx2, cancel2 := context.WithCancel(ctx)
+	defer cancel2()
+	go worker2.Run(wctx2)
+
+	waitFor(t, "variants of second photo after restart", func() bool {
+		got, err := st2.photos.Get(ctx, p2.ID, user.ID)
+		return err == nil && got.ThumbURL != "" && got.PreviewURL != ""
+	})
+}
+
+func TestJWTSecretPersistsAcrossRestart(t *testing.T) {
+	ctx := context.Background()
+	path := filepath.Join(t.TempDir(), "galo.db")
+	migFS, err := fs.Sub(assets.Migrations, "migrations/sqlite")
+	if err != nil {
+		t.Fatalf("migrations fs: %v", err)
+	}
+
+	open := func() (*sql.DB, store.Repos) {
+		t.Helper()
+		if err := db.MigrateSQLite(path, migFS); err != nil {
+			t.Fatalf("migrate: %v", err)
+		}
+		database, err := db.OpenSQLite(path)
+		if err != nil {
+			t.Fatalf("open: %v", err)
+		}
+		return database, store.NewSQLite(database)
+	}
+
+	db1, repos1 := open()
+	secret1, err := repos1.Settings.Ensure(ctx, settings.JWTSecretKey, settings.GenerateSecret)
+	if err != nil || secret1 == "" {
+		t.Fatalf("ensure secret: %v %q", err, secret1)
+	}
+	tm1 := auth.NewTokenManager(secret1, 15*time.Minute, time.Hour)
+	token, err := tm1.GenerateAccess("user-1", "u@test.local")
+	if err != nil {
+		t.Fatalf("generate: %v", err)
+	}
+	_ = db1.Close()
+
+	db2, repos2 := open()
+	defer db2.Close()
+	secret2, err := repos2.Settings.Ensure(ctx, settings.JWTSecretKey, settings.GenerateSecret)
+	if err != nil {
+		t.Fatalf("ensure after restart: %v", err)
+	}
+	if secret2 != secret1 {
+		t.Fatalf("secret changed across restart")
+	}
+	tm2 := auth.NewTokenManager(secret2, 15*time.Minute, time.Hour)
+	if _, err := tm2.ParseAccess(token); err != nil {
+		t.Fatalf("token issued before restart not valid after: %v", err)
+	}
+}
+
+func waitFor(t *testing.T, what string, cond func() bool) {
+	t.Helper()
+	deadline := time.Now().Add(10 * time.Second)
+	for time.Now().Before(deadline) {
+		if cond() {
+			return
+		}
+		time.Sleep(20 * time.Millisecond)
+	}
+	t.Fatalf("timed out waiting for %s", what)
+}

backend/internal/members/repository.go

@@ -0,0 +1,19 @@
+package members
+
+import (
+	"context"
+
+	"shared-album/internal/models"
+)
+
+// Repository is the persistence contract for the members domain.
+type Repository interface {
+	Role(ctx context.Context, albumID, userID string) (string, error)
+	List(ctx context.Context, albumID string) ([]models.AlbumMember, error)
+	Add(ctx context.Context, albumID, userID, role string, invitedBy *string) error
+	UpdateRole(ctx context.Context, albumID, userID, role string) error
+	Remove(ctx context.Context, albumID, userID string) error
+	CreateInvite(ctx context.Context, inv *models.Invite) error
+	GetInviteByToken(ctx context.Context, token string) (*models.Invite, error)
+	IncrementUses(ctx context.Context, id string) error
+}

backend/internal/members/service.go

@@ -21,13 +21,13 @@ type Notifier interface {
 }
 
 type Service struct {
-	store  *Store
+	store  Repository
 	albums AlbumReader
 	hub    *sse.Hub
 	notify Notifier
 }
 
-func NewService(store *Store, albums AlbumReader, hub *sse.Hub, notify Notifier) *Service {
+func NewService(store Repository, albums AlbumReader, hub *sse.Hub, notify Notifier) *Service {
 	return &Service{store: store, albums: albums, hub: hub, notify: notify}
 }
 

backend/internal/members/sqlite_store.go

@@ -0,0 +1,133 @@
+package members
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+
+	"shared-album/internal/models"
+	"shared-album/internal/sqliteutil"
+)
+
+// SQLiteStore is the SQLite implementation of Repository.
+type SQLiteStore struct {
+	db *sql.DB
+}
+
+func NewSQLiteStore(db *sql.DB) *SQLiteStore { return &SQLiteStore{db: db} }
+
+func (s *SQLiteStore) Role(ctx context.Context, albumID, userID string) (string, error) {
+	var role string
+	err := s.db.QueryRowContext(ctx,
+		`SELECT role FROM album_members WHERE album_id = $1 AND user_id = $2`,
+		albumID, userID).Scan(&role)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return "", nil
+		}
+		return "", err
+	}
+	return role, nil
+}
+
+func (s *SQLiteStore) List(ctx context.Context, albumID string) ([]models.AlbumMember, error) {
+	rows, err := s.db.QueryContext(ctx,
+		`SELECT m.album_id, m.user_id, m.role, m.invited_by, m.joined_at,
+		        u.id, u.email, u.name, COALESCE(u.avatar_url, '')
+		 FROM album_members m
+		 JOIN users u ON u.id = m.user_id
+		 WHERE m.album_id = $1
+		 ORDER BY m.joined_at`, albumID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	out := []models.AlbumMember{}
+	for rows.Next() {
+		var m models.AlbumMember
+		var invitedBy sql.NullString
+		var joinedAt string
+		if err := rows.Scan(&m.AlbumID, &m.UserID, &m.Role, &invitedBy, &joinedAt,
+			&m.User.ID, &m.User.Email, &m.User.Name, &m.User.AvatarURL); err != nil {
+			return nil, err
+		}
+		if invitedBy.Valid {
+			m.InvitedBy = &invitedBy.String
+		}
+		m.JoinedAt = sqliteutil.ParseTime(joinedAt)
+		out = append(out, m)
+	}
+	return out, rows.Err()
+}
+
+func (s *SQLiteStore) Add(ctx context.Context, albumID, userID, role string, invitedBy *string) error {
+	_, err := s.db.ExecContext(ctx,
+		`INSERT INTO album_members (album_id, user_id, role, invited_by)
+		 VALUES ($1, $2, $3, $4)
+		 ON CONFLICT (album_id, user_id) DO UPDATE SET role = excluded.role`,
+		albumID, userID, role, invitedBy)
+	return err
+}
+
+func (s *SQLiteStore) UpdateRole(ctx context.Context, albumID, userID, role string) error {
+	res, err := s.db.ExecContext(ctx,
+		`UPDATE album_members SET role = $3 WHERE album_id = $1 AND user_id = $2`,
+		albumID, userID, role)
+	if err != nil {
+		return err
+	}
+	if n, _ := res.RowsAffected(); n == 0 {
+		return ErrNotFound
+	}
+	return nil
+}
+
+func (s *SQLiteStore) Remove(ctx context.Context, albumID, userID string) error {
+	res, err := s.db.ExecContext(ctx,
+		`DELETE FROM album_members WHERE album_id = $1 AND user_id = $2`, albumID, userID)
+	if err != nil {
+		return err
+	}
+	if n, _ := res.RowsAffected(); n == 0 {
+		return ErrNotFound
+	}
+	return nil
+}
+
+func (s *SQLiteStore) CreateInvite(ctx context.Context, inv *models.Invite) error {
+	var createdAt string
+	err := s.db.QueryRowContext(ctx,
+		`INSERT INTO invites (id, album_id, token, role, created_by, expires_at, max_uses)
+		 VALUES ($1, $2, $3, $4, $5, $6, $7)
+		 RETURNING created_at`,
+		inv.ID, inv.AlbumID, inv.Token, inv.Role, inv.CreatedBy, sqliteutil.FormatTime(inv.ExpiresAt), inv.MaxUses,
+	).Scan(&createdAt)
+	if err != nil {
+		return err
+	}
+	inv.CreatedAt = sqliteutil.ParseTime(createdAt)
+	return nil
+}
+
+func (s *SQLiteStore) GetInviteByToken(ctx context.Context, token string) (*models.Invite, error) {
+	var inv models.Invite
+	var expiresAt, createdAt string
+	err := s.db.QueryRowContext(ctx,
+		`SELECT id, album_id, token, role, created_by, expires_at, max_uses, uses, created_at
+		 FROM invites WHERE token = $1`, token).
+		Scan(&inv.ID, &inv.AlbumID, &inv.Token, &inv.Role, &inv.CreatedBy, &expiresAt, &inv.MaxUses, &inv.Uses, &createdAt)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, ErrNotFound
+		}
+		return nil, err
+	}
+	inv.ExpiresAt = sqliteutil.ParseTime(expiresAt)
+	inv.CreatedAt = sqliteutil.ParseTime(createdAt)
+	return &inv, nil
+}
+
+func (s *SQLiteStore) IncrementUses(ctx context.Context, id string) error {
+	_, err := s.db.ExecContext(ctx, `UPDATE invites SET uses = uses + 1 WHERE id = $1`, id)
+	return err
+}

backend/internal/notifications/repository.go

@@ -0,0 +1,14 @@
+package notifications
+
+import (
+	"context"
+
+	"shared-album/internal/models"
+)
+
+// Repository is the persistence contract for the notifications domain.
+type Repository interface {
+	Create(ctx context.Context, n *models.Notification) error
+	List(ctx context.Context, userID string, limit int) ([]models.Notification, error)
+	MarkRead(ctx context.Context, id, userID string) error
+}

backend/internal/notifications/service.go

@@ -10,11 +10,11 @@ import (
 )
 
 type Service struct {
-	store *Store
+	store Repository
 	hub   *sse.Hub
 }
 
-func NewService(store *Store, hub *sse.Hub) *Service {
+func NewService(store Repository, hub *sse.Hub) *Service {
 	return &Service{store: store, hub: hub}
 }
 

backend/internal/notifications/sqlite_store.go

@@ -0,0 +1,88 @@
+package notifications
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"errors"
+	"time"
+
+	"shared-album/internal/models"
+	"shared-album/internal/sqliteutil"
+)
+
+// SQLiteStore is the SQLite implementation of Repository.
+type SQLiteStore struct {
+	db *sql.DB
+}
+
+func NewSQLiteStore(db *sql.DB) *SQLiteStore { return &SQLiteStore{db: db} }
+
+func (s *SQLiteStore) Create(ctx context.Context, n *models.Notification) error {
+	payload, err := json.Marshal(n.PayloadJSON)
+	if err != nil {
+		return err
+	}
+	var createdAt string
+	err = s.db.QueryRowContext(ctx,
+		`INSERT INTO notifications (id, user_id, type, payload_json)
+		 VALUES ($1, $2, $3, $4)
+		 RETURNING created_at`,
+		n.ID, n.UserID, n.Type, string(payload)).Scan(&createdAt)
+	if err != nil {
+		return err
+	}
+	n.CreatedAt = sqliteutil.ParseTime(createdAt)
+	return nil
+}
+
+func (s *SQLiteStore) List(ctx context.Context, userID string, limit int) ([]models.Notification, error) {
+	if limit <= 0 || limit > 200 {
+		limit = 100
+	}
+	rows, err := s.db.QueryContext(ctx,
+		`SELECT id, user_id, type, payload_json, read_at, created_at
+		 FROM notifications
+		 WHERE user_id = $1
+		 ORDER BY created_at DESC
+		 LIMIT $2`, userID, limit)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	out := []models.Notification{}
+	for rows.Next() {
+		var n models.Notification
+		var payload, createdAt string
+		var readAt sql.NullString
+		if err := rows.Scan(&n.ID, &n.UserID, &n.Type, &payload, &readAt, &createdAt); err != nil {
+			return nil, err
+		}
+		_ = json.Unmarshal([]byte(payload), &n.PayloadJSON)
+		n.ReadAt = sqliteutil.ParseNullTime(readAt)
+		n.CreatedAt = sqliteutil.ParseTime(createdAt)
+		out = append(out, n)
+	}
+	return out, rows.Err()
+}
+
+func (s *SQLiteStore) MarkRead(ctx context.Context, id, userID string) error {
+	res, err := s.db.ExecContext(ctx,
+		`UPDATE notifications SET read_at = $3 WHERE id = $1 AND user_id = $2 AND read_at IS NULL`,
+		id, userID, sqliteutil.FormatTime(time.Now()))
+	if err != nil {
+		return err
+	}
+	if n, _ := res.RowsAffected(); n == 0 {
+		var exists int
+		err := s.db.QueryRowContext(ctx,
+			`SELECT 1 FROM notifications WHERE id = $1 AND user_id = $2`, id, userID).Scan(&exists)
+		if err != nil {
+			if errors.Is(err, sql.ErrNoRows) {
+				return ErrNotFound
+			}
+			return err
+		}
+	}
+	return nil
+}

backend/internal/photos/copy_test.go

@@ -0,0 +1,92 @@
+package photos
+
+import (
+	"context"
+	"testing"
+	"time"
+)
+
+func TestCopySharesStorageObjects(t *testing.T) {
+	pool := testPool(t)
+	ctx := context.Background()
+	svc, cl := newTestService(t, pool)
+	user := createUser(t, ctx, pool)
+	albumA := createAlbum(t, ctx, pool, user)
+	albumB := createAlbum(t, ctx, pool, user)
+
+	p, err := svc.Upload(ctx, UploadInput{
+		AlbumID: albumA, UserID: user, Filename: "p.png", MimeType: "image/png", Data: makePNG(t),
+	})
+	if err != nil {
+		t.Fatalf("upload: %v", err)
+	}
+	t.Cleanup(func() { cleanupPhoto(t, ctx, pool, cl, p.ID) })
+
+	w := NewWorker(svc, time.Second, 10, time.Minute)
+	w.processVariantJobs(ctx)
+
+	srcIDs, err := svc.store.PhotoObjectIDs(ctx, p.ID)
+	if err != nil || len(srcIDs) != 3 {
+		t.Fatalf("source objects = %v err=%v", srcIDs, err)
+	}
+
+	clones, err := svc.CopyBatch(ctx, []string{p.ID}, user, albumB)
+	if err != nil || len(clones) != 1 {
+		t.Fatalf("copy: %v len=%d", err, len(clones))
+	}
+	clone := clones[0]
+	t.Cleanup(func() { cleanupPhoto(t, ctx, pool, cl, clone.ID) })
+
+	cloneIDs, err := svc.store.PhotoObjectIDs(ctx, clone.ID)
+	if err != nil || len(cloneIDs) != 3 {
+		t.Fatalf("clone objects = %v err=%v", cloneIDs, err)
+	}
+	if !sameSet(srcIDs, cloneIDs) {
+		t.Fatalf("clone does not share objects: src=%v clone=%v", srcIDs, cloneIDs)
+	}
+	for _, id := range cloneIDs {
+		if n, err := svc.store.ObjectRefCount(ctx, id); err != nil || n != 2 {
+			t.Fatalf("object %s ref count = %d err=%v, want 2", id, n, err)
+		}
+	}
+
+	// Move the source into the same album; the storage key and shared objects
+	// must be untouched.
+	beforeKey := p.StorageKey
+	moved, err := svc.MoveBatch(ctx, []string{p.ID}, user, albumB)
+	if err != nil || moved != 1 {
+		t.Fatalf("move: %v moved=%d", err, moved)
+	}
+	after, err := svc.store.GetByID(ctx, p.ID, "")
+	if err != nil {
+		t.Fatalf("get after move: %v", err)
+	}
+	if after.AlbumID != albumB {
+		t.Fatalf("photo not moved: album=%q", after.AlbumID)
+	}
+	if after.StorageKey != beforeKey {
+		t.Fatalf("move changed storage key: %q -> %q", beforeKey, after.StorageKey)
+	}
+	for _, id := range cloneIDs {
+		if n, err := svc.store.ObjectRefCount(ctx, id); err != nil || n != 2 {
+			t.Fatalf("object %s ref count after move = %d err=%v, want 2", id, n, err)
+		}
+	}
+}
+
+func sameSet(a, b []string) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	m := make(map[string]int, len(a))
+	for _, v := range a {
+		m[v]++
+	}
+	for _, v := range b {
+		m[v]--
+		if m[v] < 0 {
+			return false
+		}
+	}
+	return true
+}

backend/internal/photos/helpers_test.go

@@ -0,0 +1,167 @@
+package photos
+
+import (
+	"bytes"
+	"context"
+	"image"
+	"image/color"
+	"image/png"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+
+	"shared-album/internal/auth"
+	"shared-album/internal/config"
+	"shared-album/internal/models"
+	"shared-album/internal/roles"
+	"shared-album/internal/sse"
+	"shared-album/internal/storage"
+)
+
+func testPool(t *testing.T) *pgxpool.Pool {
+	t.Helper()
+	dsn := os.Getenv("TEST_DATABASE_URL")
+	if dsn == "" {
+		t.Skip("TEST_DATABASE_URL not set")
+	}
+	pool, err := pgxpool.New(context.Background(), dsn)
+	if err != nil {
+		t.Skipf("cannot connect: %v", err)
+	}
+	if err := pool.Ping(context.Background()); err != nil {
+		t.Skipf("cannot ping: %v", err)
+	}
+	t.Cleanup(pool.Close)
+	return pool
+}
+
+func testEnvOr(key, fallback string) string {
+	if v := os.Getenv(key); v != "" {
+		return v
+	}
+	return fallback
+}
+
+type stubAlbums struct{}
+
+func (stubAlbums) Access(ctx context.Context, albumID, userID string) (*models.Album, string, error) {
+	return &models.Album{ID: albumID}, roles.Owner, nil
+}
+
+func createUser(t *testing.T, ctx context.Context, pool *pgxpool.Pool) string {
+	t.Helper()
+	id := auth.NewID()
+	if _, err := pool.Exec(ctx,
+		`INSERT INTO users (id, email, password_hash, name) VALUES ($1, $2, 'x', 't')`,
+		id, id+"@test.local"); err != nil {
+		t.Fatalf("create user: %v", err)
+	}
+	t.Cleanup(func() { _, _ = pool.Exec(ctx, `DELETE FROM users WHERE id = $1`, id) })
+	return id
+}
+
+func createAlbum(t *testing.T, ctx context.Context, pool *pgxpool.Pool, ownerID string) string {
+	t.Helper()
+	id := auth.NewID()
+	if _, err := pool.Exec(ctx,
+		`INSERT INTO albums (id, owner_id, title) VALUES ($1, $2, 't')`, id, ownerID); err != nil {
+		t.Fatalf("create album: %v", err)
+	}
+	t.Cleanup(func() { _, _ = pool.Exec(ctx, `DELETE FROM albums WHERE id = $1`, id) })
+	return id
+}
+
+func createPhoto(t *testing.T, ctx context.Context, pool *pgxpool.Pool, uploaderID string) string {
+	t.Helper()
+	id := auth.NewID()
+	if _, err := pool.Exec(ctx,
+		`INSERT INTO photos (id, album_id, uploader_id) VALUES ($1, NULL, $2)`, id, uploaderID); err != nil {
+		t.Fatalf("create photo: %v", err)
+	}
+	return id
+}
+
+func makePNG(t *testing.T) []byte {
+	t.Helper()
+	img := image.NewRGBA(image.Rect(0, 0, 4, 4))
+	for x := 0; x < 4; x++ {
+		for y := 0; y < 4; y++ {
+			img.Set(x, y, color.RGBA{R: uint8(x * 40), G: uint8(y * 40), B: 128, A: 255})
+		}
+	}
+	var buf bytes.Buffer
+	if err := png.Encode(&buf, img); err != nil {
+		t.Fatalf("encode png: %v", err)
+	}
+	return buf.Bytes()
+}
+
+// newTestService builds a service backed by the real dev storage. It skips when
+// S3 env is absent so unit runs stay hermetic.
+func newTestService(t *testing.T, pool *pgxpool.Pool) (*Service, storage.Backend) {
+	t.Helper()
+	endpoint := os.Getenv("S3_ENDPOINT")
+	if endpoint == "" {
+		t.Skip("S3_ENDPOINT not set")
+	}
+	signer, err := storage.NewSigner("http://app.test", "test-secret", time.Hour)
+	if err != nil {
+		t.Skipf("signer init: %v", err)
+	}
+	cl, err := storage.NewS3(context.Background(), config.S3{
+		Endpoint:     endpoint,
+		Region:       testEnvOr("S3_REGION", "garage"),
+		AccessKey:    os.Getenv("S3_ACCESS_KEY"),
+		SecretKey:    os.Getenv("S3_SECRET_KEY"),
+		Bucket:       testEnvOr("S3_BUCKET", "galo-data"),
+		UsePathStyle: testEnvOr("S3_USE_PATH_STYLE", "true") != "false",
+	}, signer)
+	if err != nil {
+		t.Skipf("storage init: %v", err)
+	}
+	return NewService(NewStore(pool), stubAlbums{}, cl, sse.NewHub(1)), cl
+}
+
+// newTestServiceFS builds a service backed by a temporary local file-system
+// storage backend so the full flow can run without external infrastructure.
+func newTestServiceFS(t *testing.T, pool *pgxpool.Pool) (*Service, storage.Backend) {
+	t.Helper()
+	signer, err := storage.NewSigner("http://app.test", "test-secret", time.Hour)
+	if err != nil {
+		t.Fatalf("storage init: %v", err)
+	}
+	fs, err := storage.NewFS(t.TempDir(), signer)
+	if err != nil {
+		t.Fatalf("storage init: %v", err)
+	}
+	return NewService(NewStore(pool), stubAlbums{}, fs, sse.NewHub(1)), fs
+}
+
+// cleanupPhoto removes a photo, its objects (rows and blobs) and bindings.
+func cleanupPhoto(t *testing.T, ctx context.Context, pool *pgxpool.Pool, cl storage.Backend, photoID string) {
+	t.Helper()
+	rows, err := pool.Query(ctx,
+		`SELECT o.id, o.storage_key FROM photo_objects po JOIN objects o ON o.id = po.object_id
+		 WHERE po.photo_id = $1`, photoID)
+	if err != nil {
+		return
+	}
+	var ids, keys []string
+	for rows.Next() {
+		var id, key string
+		if rows.Scan(&id, &key) == nil {
+			ids = append(ids, id)
+			keys = append(keys, key)
+		}
+	}
+	rows.Close()
+	_, _ = pool.Exec(ctx, `DELETE FROM photos WHERE id = $1`, photoID)
+	for _, id := range ids {
+		_, _ = pool.Exec(ctx, `DELETE FROM objects WHERE id = $1`, id)
+	}
+	if cl != nil && len(keys) > 0 {
+		_ = cl.Delete(ctx, keys...)
+	}
+}

backend/internal/photos/keys.go

@@ -0,0 +1,17 @@
+package photos
+
+import (
+	"fmt"
+	"strings"
+)
+
+// objectKey builds an opaque, album-free storage key for a physical object.
+// The key never encodes album, photo or any other metadata entity; the mapping
+// between a key and its photo binding lives only in the metadata layer. The
+// role segment is cosmetic (for debugging) and is not authoritative.
+func objectKey(objectID, role, ext string) string {
+	if ext != "" && !strings.HasPrefix(ext, ".") {
+		ext = "." + ext
+	}
+	return fmt.Sprintf("objects/%s/%s%s", objectID, role, ext)
+}

backend/internal/photos/keys_test.go

@@ -0,0 +1,32 @@
+package photos
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestObjectKeyIsAlbumFree(t *testing.T) {
+	cases := []struct {
+		name string
+		id   string
+		role string
+		ext  string
+		want string
+	}{
+		{"original with dot", "obj1", RoleOriginal, ".jpg", "objects/obj1/original.jpg"},
+		{"thumb without dot", "obj1", RoleThumb, "webp", "objects/obj1/thumb.webp"},
+		{"preview", "obj2", RolePreview, ".webp", "objects/obj2/preview.webp"},
+		{"empty ext", "obj3", RoleOriginal, "", "objects/obj3/original"},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			got := objectKey(tc.id, tc.role, tc.ext)
+			if got != tc.want {
+				t.Fatalf("objectKey = %q, want %q", got, tc.want)
+			}
+			if strings.Contains(got, "album") {
+				t.Fatalf("key must not encode an album entity: %q", got)
+			}
+		})
+	}
+}

backend/internal/photos/objects.go

@@ -0,0 +1,388 @@
+package photos
+
+import (
+	"context"
+	"errors"
+	"time"
+
+	"github.com/jackc/pgx/v5"
+)
+
+// Object lifecycle states. The DB row is the ledger entry that governs the
+// lifecycle of the corresponding blob in the storage layer.
+const (
+	ObjectPending  = "pending"
+	ObjectReady    = "ready"
+	ObjectDeleting = "deleting"
+)
+
+// Object roles as bound to a photo. The role is a property of the binding.
+const (
+	RoleOriginal = "original"
+	RoleThumb    = "thumb"
+	RolePreview  = "preview"
+)
+
+var (
+	// ErrObjectNotFound is returned when an object row does not exist.
+	ErrObjectNotFound = errors.New("object not found")
+	// ErrObjectNotReady is returned when binding an object that is not ready.
+	ErrObjectNotReady = errors.New("object is not ready")
+)
+
+// Object is a physical file in the storage layer, described by metadata.
+type Object struct {
+	ID         string
+	StorageKey string
+	MimeType   string
+	Size       int64
+	Width      int
+	Height     int
+	Checksum   string
+	State      string
+	CreatedAt  time.Time
+}
+
+// CreateObject inserts a new object row in the pending state.
+func (s *Store) CreateObject(ctx context.Context, o *Object) error {
+	if o.State == "" {
+		o.State = ObjectPending
+	}
+	return s.pool.QueryRow(ctx,
+		`INSERT INTO objects (id, storage_key, mime_type, size, width, height, checksum, state)
+		 VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+		 RETURNING created_at`,
+		o.ID, o.StorageKey, o.MimeType, o.Size, o.Width, o.Height, o.Checksum, o.State).Scan(&o.CreatedAt)
+}
+
+// SetObjectState updates an object's lifecycle state.
+func (s *Store) SetObjectState(ctx context.Context, id, state string) error {
+	tag, err := s.pool.Exec(ctx, `UPDATE objects SET state = $2 WHERE id = $1`, id, state)
+	if err != nil {
+		return err
+	}
+	if tag.RowsAffected() == 0 {
+		return ErrObjectNotFound
+	}
+	return nil
+}
+
+// ActivateObject marks an object ready after its bytes have been stored.
+func (s *Store) ActivateObject(ctx context.Context, id string) error {
+	return s.SetObjectState(ctx, id, ObjectReady)
+}
+
+// MarkObjectDeleting marks an object as pending removal from storage.
+func (s *Store) MarkObjectDeleting(ctx context.Context, id string) error {
+	return s.SetObjectState(ctx, id, ObjectDeleting)
+}
+
+// DeleteObjectRow permanently removes an object row (after its blob is gone).
+func (s *Store) DeleteObjectRow(ctx context.Context, id string) error {
+	tag, err := s.pool.Exec(ctx, `DELETE FROM objects WHERE id = $1`, id)
+	if err != nil {
+		return err
+	}
+	if tag.RowsAffected() == 0 {
+		return ErrObjectNotFound
+	}
+	return nil
+}
+
+// BindObject attaches a ready object to a photo under the given role. It locks
+// the object row and refuses objects that are not ready, so an object being
+// garbage-collected can never be bound.
+func (s *Store) BindObject(ctx context.Context, photoID, objectID, role string) error {
+	tx, err := s.pool.Begin(ctx)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = tx.Rollback(ctx) }()
+
+	var state string
+	if err := tx.QueryRow(ctx, `SELECT state FROM objects WHERE id = $1 FOR UPDATE`, objectID).Scan(&state); err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return ErrObjectNotFound
+		}
+		return err
+	}
+	if state != ObjectReady {
+		return ErrObjectNotReady
+	}
+	if _, err := tx.Exec(ctx,
+		`INSERT INTO photo_objects (photo_id, object_id, role) VALUES ($1, $2, $3)
+		 ON CONFLICT (photo_id, role) DO UPDATE SET object_id = EXCLUDED.object_id`,
+		photoID, objectID, role); err != nil {
+		return err
+	}
+	return tx.Commit(ctx)
+}
+
+// PhotoObjectIDs returns the object ids currently bound to a photo.
+func (s *Store) PhotoObjectIDs(ctx context.Context, photoID string) ([]string, error) {
+	rows, err := s.pool.Query(ctx, `SELECT object_id FROM photo_objects WHERE photo_id = $1`, photoID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var ids []string
+	for rows.Next() {
+		var id string
+		if err := rows.Scan(&id); err != nil {
+			return nil, err
+		}
+		ids = append(ids, id)
+	}
+	return ids, rows.Err()
+}
+
+// ObjectRefCount counts how many photo bindings reference an object.
+func (s *Store) ObjectRefCount(ctx context.Context, objectID string) (int, error) {
+	var n int
+	err := s.pool.QueryRow(ctx, `SELECT count(*) FROM photo_objects WHERE object_id = $1`, objectID).Scan(&n)
+	return n, err
+}
+
+// OriginalObject returns the original object bound to a photo.
+func (s *Store) OriginalObject(ctx context.Context, photoID string) (*Object, error) {
+	var o Object
+	err := s.pool.QueryRow(ctx,
+		`SELECT o.id, o.storage_key, o.mime_type, o.size, o.width, o.height, o.checksum, o.state, o.created_at
+		 FROM photo_objects po JOIN objects o ON o.id = po.object_id
+		 WHERE po.photo_id = $1 AND po.role = $2`, photoID, RoleOriginal).
+		Scan(&o.ID, &o.StorageKey, &o.MimeType, &o.Size, &o.Width, &o.Height, &o.Checksum, &o.State, &o.CreatedAt)
+	if err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return nil, ErrObjectNotFound
+		}
+		return nil, err
+	}
+	return &o, nil
+}
+
+// PhotosByOriginalObject returns the ids of all photos bound to the given
+// original object, so generated variants can be shared between copies.
+func (s *Store) PhotosByOriginalObject(ctx context.Context, originalObjectID string) ([]string, error) {
+	rows, err := s.pool.Query(ctx,
+		`SELECT photo_id FROM photo_objects WHERE object_id = $1 AND role = $2`, originalObjectID, RoleOriginal)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var ids []string
+	for rows.Next() {
+		var id string
+		if err := rows.Scan(&id); err != nil {
+			return nil, err
+		}
+		ids = append(ids, id)
+	}
+	return ids, rows.Err()
+}
+
+// ClaimGarbage claims collectible objects: ready objects with no bindings and
+// objects already marked deleting. Rows are locked with SKIP LOCKED so
+// concurrent workers do not contend and a concurrent bind cannot slip in.
+func (s *Store) ClaimGarbage(ctx context.Context, limit int) ([]Object, error) {
+	if limit <= 0 {
+		limit = 10
+	}
+	tx, err := s.pool.Begin(ctx)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = tx.Rollback(ctx) }()
+
+	rows, err := tx.Query(ctx,
+		`SELECT o.id, o.storage_key FROM objects o
+		 WHERE o.state = ANY($1)
+		   AND NOT EXISTS (SELECT 1 FROM photo_objects po WHERE po.object_id = o.id)
+		 ORDER BY o.created_at
+		 LIMIT $2
+		 FOR UPDATE SKIP LOCKED`, []string{ObjectReady, ObjectDeleting}, limit)
+	if err != nil {
+		return nil, err
+	}
+	var objs []Object
+	for rows.Next() {
+		var o Object
+		if err := rows.Scan(&o.ID, &o.StorageKey); err != nil {
+			rows.Close()
+			return nil, err
+		}
+		objs = append(objs, o)
+	}
+	rows.Close()
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	if len(objs) == 0 {
+		return nil, tx.Commit(ctx)
+	}
+	ids := make([]string, len(objs))
+	for i, o := range objs {
+		ids[i] = o.ID
+	}
+	if _, err := tx.Exec(ctx, `UPDATE objects SET state = $2 WHERE id = ANY($1)`, ids, ObjectDeleting); err != nil {
+		return nil, err
+	}
+	if err := tx.Commit(ctx); err != nil {
+		return nil, err
+	}
+	return objs, nil
+}
+
+// ClaimStalePending marks abandoned pending objects (whose upload never
+// completed) as deleting and returns them for cleanup.
+func (s *Store) ClaimStalePending(ctx context.Context, olderThan time.Duration, limit int) ([]Object, error) {
+	if limit <= 0 {
+		limit = 10
+	}
+	tx, err := s.pool.Begin(ctx)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = tx.Rollback(ctx) }()
+
+	rows, err := tx.Query(ctx,
+		`SELECT id, storage_key FROM objects
+		 WHERE state = $1 AND created_at < $2
+		 ORDER BY created_at
+		 LIMIT $3
+		 FOR UPDATE SKIP LOCKED`, ObjectPending, time.Now().Add(-olderThan), limit)
+	if err != nil {
+		return nil, err
+	}
+	var objs []Object
+	for rows.Next() {
+		var o Object
+		if err := rows.Scan(&o.ID, &o.StorageKey); err != nil {
+			rows.Close()
+			return nil, err
+		}
+		objs = append(objs, o)
+	}
+	rows.Close()
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	if len(objs) == 0 {
+		return nil, tx.Commit(ctx)
+	}
+	ids := make([]string, len(objs))
+	for i, o := range objs {
+		ids[i] = o.ID
+	}
+	if _, err := tx.Exec(ctx, `UPDATE objects SET state = $2 WHERE id = ANY($1)`, ids, ObjectDeleting); err != nil {
+		return nil, err
+	}
+	if err := tx.Commit(ctx); err != nil {
+		return nil, err
+	}
+	return objs, nil
+}
+
+// ClaimVariantJobs leases due variant jobs and returns their photo ids. The
+// lease pushes next_attempt_at forward so the same job is not picked up twice
+// while it is being processed.
+func (s *Store) ClaimVariantJobs(ctx context.Context, limit int, lease time.Duration) ([]string, error) {
+	if limit <= 0 {
+		limit = 10
+	}
+	tx, err := s.pool.Begin(ctx)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = tx.Rollback(ctx) }()
+
+	rows, err := tx.Query(ctx,
+		`SELECT photo_id FROM variant_jobs
+		 WHERE next_attempt_at <= now()
+		 ORDER BY next_attempt_at
+		 LIMIT $1
+		 FOR UPDATE SKIP LOCKED`, limit)
+	if err != nil {
+		return nil, err
+	}
+	var ids []string
+	for rows.Next() {
+		var id string
+		if err := rows.Scan(&id); err != nil {
+			rows.Close()
+			return nil, err
+		}
+		ids = append(ids, id)
+	}
+	rows.Close()
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	if len(ids) == 0 {
+		return nil, tx.Commit(ctx)
+	}
+	if _, err := tx.Exec(ctx,
+		`UPDATE variant_jobs SET next_attempt_at = $2 WHERE photo_id = ANY($1)`,
+		ids, time.Now().Add(lease)); err != nil {
+		return nil, err
+	}
+	if err := tx.Commit(ctx); err != nil {
+		return nil, err
+	}
+	return ids, nil
+}
+
+// CompleteVariantJob removes a finished job.
+func (s *Store) CompleteVariantJob(ctx context.Context, photoID string) error {
+	_, err := s.pool.Exec(ctx, `DELETE FROM variant_jobs WHERE photo_id = $1`, photoID)
+	return err
+}
+
+// FailVariantJob records a failure and schedules a retry with exponential
+// backoff. After maxAttempts the job is abandoned so a permanently broken photo
+// cannot loop forever.
+func (s *Store) FailVariantJob(ctx context.Context, photoID, errMsg string, maxAttempts int) error {
+	tx, err := s.pool.Begin(ctx)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = tx.Rollback(ctx) }()
+
+	var attempts int
+	err = tx.QueryRow(ctx,
+		`UPDATE variant_jobs
+		 SET attempts = attempts + 1,
+		     next_attempt_at = now() + make_interval(secs => least(300, 10 * power(2, attempts))),
+		     last_error = $2
+		 WHERE photo_id = $1
+		 RETURNING attempts`, photoID, errMsg).Scan(&attempts)
+	if err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return tx.Commit(ctx)
+		}
+		return err
+	}
+	if maxAttempts > 0 && attempts >= maxAttempts {
+		if _, err := tx.Exec(ctx, `DELETE FROM variant_jobs WHERE photo_id = $1`, photoID); err != nil {
+			return err
+		}
+	}
+	return tx.Commit(ctx)
+}
+
+// AllStorageKeys returns every key registered in the object journal.
+func (s *Store) AllStorageKeys(ctx context.Context) ([]string, error) {
+	rows, err := s.pool.Query(ctx, `SELECT storage_key FROM objects`)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var keys []string
+	for rows.Next() {
+		var k string
+		if err := rows.Scan(&k); err != nil {
+			return nil, err
+		}
+		keys = append(keys, k)
+	}
+	return keys, rows.Err()
+}

backend/internal/photos/objects_test.go

@@ -0,0 +1,187 @@
+package photos
+
+import (
+	"context"
+	"errors"
+	"testing"
+	"time"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+
+	"shared-album/internal/auth"
+)
+
+func TestObjectStateTransitions(t *testing.T) {
+	pool := testPool(t)
+	ctx := context.Background()
+	st := NewStore(pool)
+
+	objID := auth.NewID()
+	obj := &Object{ID: objID, StorageKey: "objects/" + objID + "/original.jpg", MimeType: "image/jpeg", Size: 42}
+	t.Cleanup(func() { _, _ = pool.Exec(ctx, `DELETE FROM objects WHERE id = $1`, objID) })
+
+	if err := st.CreateObject(ctx, obj); err != nil {
+		t.Fatalf("create object: %v", err)
+	}
+	if obj.State != ObjectPending {
+		t.Fatalf("new object state = %q, want %q", obj.State, ObjectPending)
+	}
+	if obj.CreatedAt.IsZero() {
+		t.Fatalf("created_at not populated")
+	}
+
+	if err := st.ActivateObject(ctx, objID); err != nil {
+		t.Fatalf("activate: %v", err)
+	}
+	if got := objectState(t, ctx, pool, objID); got != ObjectReady {
+		t.Fatalf("state after activate = %q", got)
+	}
+	if err := st.MarkObjectDeleting(ctx, objID); err != nil {
+		t.Fatalf("mark deleting: %v", err)
+	}
+	if got := objectState(t, ctx, pool, objID); got != ObjectDeleting {
+		t.Fatalf("state after mark = %q", got)
+	}
+	if err := st.DeleteObjectRow(ctx, objID); err != nil {
+		t.Fatalf("delete row: %v", err)
+	}
+	if err := st.DeleteObjectRow(ctx, objID); !errors.Is(err, ErrObjectNotFound) {
+		t.Fatalf("second delete = %v, want ErrObjectNotFound", err)
+	}
+}
+
+func TestClaimStalePending(t *testing.T) {
+	pool := testPool(t)
+	ctx := context.Background()
+	st := NewStore(pool)
+
+	objID := auth.NewID()
+	obj := &Object{ID: objID, StorageKey: "objects/" + objID + "/original.jpg"}
+	t.Cleanup(func() { _, _ = pool.Exec(ctx, `DELETE FROM objects WHERE id = $1`, objID) })
+	if err := st.CreateObject(ctx, obj); err != nil {
+		t.Fatalf("create object: %v", err)
+	}
+	if _, err := pool.Exec(ctx, `UPDATE objects SET created_at = now() - interval '1 hour' WHERE id = $1`, objID); err != nil {
+		t.Fatalf("age object: %v", err)
+	}
+
+	objs, err := st.ClaimStalePending(ctx, 10*time.Minute, 100)
+	if err != nil {
+		t.Fatalf("claim stale: %v", err)
+	}
+	if !containsObject(objs, objID) {
+		t.Fatalf("stale pending object not claimed: %+v", objs)
+	}
+	if got := objectState(t, ctx, pool, objID); got != ObjectDeleting {
+		t.Fatalf("claimed stale object state = %q, want deleting", got)
+	}
+}
+
+func TestBindObjectRequiresReadyAndShares(t *testing.T) {
+	pool := testPool(t)
+	ctx := context.Background()
+	st := NewStore(pool)
+
+	user := createUser(t, ctx, pool)
+	p1 := createPhoto(t, ctx, pool, user)
+	p2 := createPhoto(t, ctx, pool, user)
+
+	objID := auth.NewID()
+	obj := &Object{ID: objID, StorageKey: "objects/" + objID + "/original.jpg"}
+	t.Cleanup(func() {
+		_, _ = pool.Exec(ctx, `DELETE FROM photo_objects WHERE object_id = $1`, objID)
+		_, _ = pool.Exec(ctx, `DELETE FROM objects WHERE id = $1`, objID)
+	})
+	if err := st.CreateObject(ctx, obj); err != nil {
+		t.Fatalf("create object: %v", err)
+	}
+
+	if err := st.BindObject(ctx, p1, objID, RoleOriginal); !errors.Is(err, ErrObjectNotReady) {
+		t.Fatalf("bind pending object = %v, want ErrObjectNotReady", err)
+	}
+	if err := st.ActivateObject(ctx, objID); err != nil {
+		t.Fatalf("activate: %v", err)
+	}
+	if err := st.BindObject(ctx, p1, objID, RoleOriginal); err != nil {
+		t.Fatalf("bind p1: %v", err)
+	}
+	if err := st.BindObject(ctx, p2, objID, RoleOriginal); err != nil {
+		t.Fatalf("bind p2: %v", err)
+	}
+
+	if n, err := st.ObjectRefCount(ctx, objID); err != nil || n != 2 {
+		t.Fatalf("ref count = %d err=%v, want 2", n, err)
+	}
+	siblings, err := st.PhotosByOriginalObject(ctx, objID)
+	if err != nil || len(siblings) != 2 {
+		t.Fatalf("siblings = %v err=%v, want 2", siblings, err)
+	}
+}
+
+func TestClaimGarbageRespectsReferences(t *testing.T) {
+	pool := testPool(t)
+	ctx := context.Background()
+	st := NewStore(pool)
+
+	user := createUser(t, ctx, pool)
+	photo := createPhoto(t, ctx, pool, user)
+
+	boundID := auth.NewID()
+	freeID := auth.NewID()
+	t.Cleanup(func() {
+		_, _ = pool.Exec(ctx, `DELETE FROM photo_objects WHERE object_id IN ($1, $2)`, boundID, freeID)
+		_, _ = pool.Exec(ctx, `DELETE FROM objects WHERE id IN ($1, $2)`, boundID, freeID)
+	})
+	for _, id := range []string{boundID, freeID} {
+		if err := st.CreateObject(ctx, &Object{ID: id, StorageKey: "objects/" + id + "/original.jpg"}); err != nil {
+			t.Fatalf("create object: %v", err)
+		}
+		if err := st.ActivateObject(ctx, id); err != nil {
+			t.Fatalf("activate: %v", err)
+		}
+	}
+	if err := st.BindObject(ctx, photo, boundID, RoleOriginal); err != nil {
+		t.Fatalf("bind: %v", err)
+	}
+
+	claimed, err := st.ClaimGarbage(ctx, 100)
+	if err != nil {
+		t.Fatalf("claim garbage: %v", err)
+	}
+	if !containsObject(claimed, freeID) {
+		t.Fatalf("unreferenced object not claimed: %+v", claimed)
+	}
+	if containsObject(claimed, boundID) {
+		t.Fatalf("referenced object was claimed for deletion")
+	}
+
+	// Removing the last reference makes both collectible.
+	if _, err := pool.Exec(ctx, `DELETE FROM photos WHERE id = $1`, photo); err != nil {
+		t.Fatalf("delete photo: %v", err)
+	}
+	claimed, err = st.ClaimGarbage(ctx, 100)
+	if err != nil {
+		t.Fatalf("claim garbage 2: %v", err)
+	}
+	if !containsObject(claimed, boundID) {
+		t.Fatalf("object with no remaining references not claimed: %+v", claimed)
+	}
+}
+
+func objectState(t *testing.T, ctx context.Context, pool *pgxpool.Pool, id string) string {
+	t.Helper()
+	var state string
+	if err := pool.QueryRow(ctx, `SELECT state FROM objects WHERE id = $1`, id).Scan(&state); err != nil {
+		t.Fatalf("read state: %v", err)
+	}
+	return state
+}
+
+func containsObject(objs []Object, id string) bool {
+	for _, o := range objs {
+		if o.ID == id {
+			return true
+		}
+	}
+	return false
+}

backend/internal/photos/pipeline.go

@@ -2,6 +2,8 @@ package photos
 
 import (
 	"bytes"
+	"crypto/sha256"
+	"encoding/hex"
 	"fmt"
 	"image"
 	"strconv"
@@ -138,3 +140,9 @@ func buildVariants(data []byte) (thumb, preview []byte, err error) {
 	}
 	return thumbBuf.Bytes(), previewBuf.Bytes(), nil
 }
+
+// checksum returns the hex-encoded SHA-256 of the given bytes.
+func checksum(data []byte) string {
+	sum := sha256.Sum256(data)
+	return hex.EncodeToString(sum[:])
+}

backend/internal/photos/repository.go

@@ -0,0 +1,52 @@
+package photos
+
+import (
+	"context"
+	"time"
+
+	"shared-album/internal/models"
+)
+
+// Repository is the persistence contract for the photos domain, including the
+// object ledger, variant queue and garbage collection.
+type Repository interface {
+	CreateWithOriginal(ctx context.Context, p *models.Photo, obj *Object) error
+	DeleteUpload(ctx context.Context, photoID, objectID string) error
+	GetByID(ctx context.Context, id, viewerID string) (*models.Photo, error)
+	List(ctx context.Context, in ListParams) ([]models.Photo, error)
+	SetDeleted(ctx context.Context, id string, deleted bool) error
+	UpdateAlbum(ctx context.Context, id, albumID string) error
+	Clone(ctx context.Context, src *models.Photo, albumID, uploaderID, id string) error
+	HardDelete(ctx context.Context, id string) error
+	ListTrash(ctx context.Context, userID string) ([]models.Photo, error)
+	TrashCount(ctx context.Context, userID string) (int, error)
+	RestoreToAlbum(ctx context.Context, id, albumID string) error
+	AlbumExists(ctx context.Context, albumID string) (bool, error)
+	ListTags(ctx context.Context, userID, q string) ([]models.Tag, error)
+	EnsureTag(ctx context.Context, userID, name string) (*models.Tag, error)
+	AttachTag(ctx context.Context, photoID, tagID string) error
+	DetachTag(ctx context.Context, photoID, tagID string) error
+	TagOwnedBy(ctx context.Context, tagID, userID string) (bool, error)
+	SetCoverIfEmpty(ctx context.Context, albumID, photoID string)
+	UpdateFilename(ctx context.Context, id, filename string) error
+	BackfillEXIF(ctx context.Context, fetch func(context.Context, string) ([]byte, error)) (int, error)
+
+	CreateObject(ctx context.Context, o *Object) error
+	SetObjectState(ctx context.Context, id, state string) error
+	ActivateObject(ctx context.Context, id string) error
+	MarkObjectDeleting(ctx context.Context, id string) error
+	DeleteObjectRow(ctx context.Context, id string) error
+	BindObject(ctx context.Context, photoID, objectID, role string) error
+	PhotoObjectIDs(ctx context.Context, photoID string) ([]string, error)
+	ObjectRefCount(ctx context.Context, objectID string) (int, error)
+	OriginalObject(ctx context.Context, photoID string) (*Object, error)
+	PhotosByOriginalObject(ctx context.Context, originalObjectID string) ([]string, error)
+	ClaimGarbage(ctx context.Context, limit int) ([]Object, error)
+	ClaimStalePending(ctx context.Context, olderThan time.Duration, limit int) ([]Object, error)
+	ClaimVariantJobs(ctx context.Context, limit int, lease time.Duration) ([]string, error)
+	CompleteVariantJob(ctx context.Context, photoID string) error
+	FailVariantJob(ctx context.Context, photoID, errMsg string, maxAttempts int) error
+
+	// AllStorageKeys returns every key registered in the object journal.
+	AllStorageKeys(ctx context.Context) ([]string, error)
+}

backend/internal/photos/service.go

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"context"
 	"errors"
-	"fmt"
 	"net/http"
 	"path/filepath"
 	"strings"
@@ -23,13 +22,13 @@ type AlbumAccess interface {
 }
 
 type Service struct {
-	store   *Store
+	store   Repository
 	albums  AlbumAccess
-	storage *storage.Client
+	storage storage.Backend
 	hub     *sse.Hub
 }
 
-func NewService(store *Store, albums AlbumAccess, storage *storage.Client, hub *sse.Hub) *Service {
+func NewService(store Repository, albums AlbumAccess, storage storage.Backend, hub *sse.Hub) *Service {
 	return &Service{store: store, albums: albums, storage: storage, hub: hub}
 }
 
@@ -64,22 +63,20 @@ func (s *Service) Upload(ctx context.Context, in UploadInput) (*models.Photo, er
 	}
 	meta := extractEXIF(in.Data)
 
-	id := auth.NewID()
 	ext := strings.ToLower(filepath.Ext(in.Filename))
 	if ext == "" {
 		ext = ".bin"
 	}
-	storageKey := fmt.Sprintf("albums/%s/original/%s%s", in.AlbumID, id, ext)
 
-	if err := s.storage.Put(ctx, storageKey, bytes.NewReader(in.Data), int64(len(in.Data)), mime); err != nil {
-		return nil, err
-	}
+	photoID := auth.NewID()
+	objectID := auth.NewID()
+	key := objectKey(objectID, RoleOriginal, ext)
 
 	p := &models.Photo{
-		ID:               id,
+		ID:               photoID,
 		AlbumID:          in.AlbumID,
 		UploaderID:       in.UserID,
-		StorageKey:       storageKey,
+		StorageKey:       key,
 		OriginalFilename: in.Filename,
 		Size:             int64(len(in.Data)),
 		Width:            width,
@@ -90,12 +87,28 @@ func (s *Service) Upload(ctx context.Context, in UploadInput) (*models.Photo, er
 		Longitude:        meta.Longitude,
 		EXIF:             meta.Attributes,
 	}
-	if err := s.store.Create(ctx, p); err != nil {
-		return nil, err
+	obj := &Object{
+		ID:         objectID,
+		StorageKey: key,
+		MimeType:   mime,
+		Size:       int64(len(in.Data)),
+		Width:      width,
+		Height:     height,
+		Checksum:   checksum(in.Data),
 	}
 
-	data := in.Data
-	go s.processVariants(p.ID, in.AlbumID, data)
+	// The metadata layer is the ledger of record: the row is written first,
+	// then the bytes are stored, then the object is activated.
+	if err := s.store.CreateWithOriginal(ctx, p, obj); err != nil {
+		return nil, err
+	}
+	if err := s.storage.Put(ctx, key, bytes.NewReader(in.Data), int64(len(in.Data)), mime); err != nil {
+		_ = s.store.DeleteUpload(ctx, photoID, objectID)
+		return nil, err
+	}
+	if err := s.store.ActivateObject(ctx, objectID); err != nil {
+		return nil, err
+	}
 
 	if err := s.attachURLs(ctx, p); err != nil {
 		return nil, err
@@ -103,36 +116,9 @@ func (s *Service) Upload(ctx context.Context, in UploadInput) (*models.Photo, er
 	return p, nil
 }
 
-func (s *Service) processVariants(photoID, albumID string, data []byte) {
-	ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
-	defer cancel()
-
-	thumb, preview, err := buildVariants(data)
-	if err != nil {
-		return
-	}
-	thumbKey := fmt.Sprintf("albums/%s/thumb/%s.webp", albumID, photoID)
-	previewKey := fmt.Sprintf("albums/%s/preview/%s.webp", albumID, photoID)
-	if err := s.storage.Put(ctx, thumbKey, bytes.NewReader(thumb), int64(len(thumb)), "image/webp"); err != nil {
-		return
-	}
-	if err := s.storage.Put(ctx, previewKey, bytes.NewReader(preview), int64(len(preview)), "image/webp"); err != nil {
-		return
-	}
-	if err := s.store.SetVariants(ctx, photoID, thumbKey, previewKey); err != nil {
-		return
-	}
-	s.store.SetCoverIfEmpty(ctx, albumID, photoID)
-	if p, err := s.store.GetByID(ctx, photoID, ""); err == nil {
-		if err := s.attachURLs(ctx, p); err == nil {
-			s.hub.Publish(albumID, "photo.created", p)
-		}
-	}
-}
-
 func (s *Service) attachURLs(ctx context.Context, p *models.Photo) error {
 	if p.StorageKey != "" {
-		url, err := s.storage.PresignGet(ctx, p.StorageKey)
+		url, err := s.storage.URL(ctx, p.StorageKey)
 		if err != nil {
 			return err
 		}
@@ -140,12 +126,12 @@ func (s *Service) attachURLs(ctx context.Context, p *models.Photo) error {
 		p.DownloadURL = url
 	}
 	if p.ThumbKey != "" {
-		if url, err := s.storage.PresignGet(ctx, p.ThumbKey); err == nil {
+		if url, err := s.storage.URL(ctx, p.ThumbKey); err == nil {
 			p.ThumbURL = url
 		}
 	}
 	if p.PreviewKey != "" {
-		if url, err := s.storage.PresignGet(ctx, p.PreviewKey); err == nil {
+		if url, err := s.storage.URL(ctx, p.PreviewKey); err == nil {
 			p.PreviewURL = url
 		}
 	}
@@ -216,13 +202,13 @@ func (s *Service) GetPublic(ctx context.Context, photoID string) (*models.Photo,
 	return p, nil
 }
 
-// DownloadPublic returns a presigned original URL for a share link.
+// DownloadPublic returns a signed original URL for a share link.
 func (s *Service) DownloadPublic(ctx context.Context, photoID string) (string, error) {
 	p, err := s.GetPublic(ctx, photoID)
 	if err != nil {
 		return "", err
 	}
-	return s.storage.PresignGet(ctx, p.StorageKey)
+	return s.storage.URL(ctx, p.StorageKey)
 }
 
 func (s *Service) Get(ctx context.Context, photoID, userID string) (*models.Photo, error) {
@@ -250,7 +236,7 @@ func (s *Service) Download(ctx context.Context, photoID, userID string) (string,
 	if err != nil {
 		return "", err
 	}
-	url, err := s.storage.PresignGet(ctx, p.StorageKey)
+	url, err := s.storage.URL(ctx, p.StorageKey)
 	if err != nil {
 		return "", err
 	}
@@ -416,21 +402,22 @@ func (s *Service) PermanentDelete(ctx context.Context, photoID, userID string) e
 	if !canDeletePhoto(role, p.UploaderID == userID) {
 		return httpx.Forbidden("forbidden", "you cannot delete this photo")
 	}
+	objectIDs, err := s.store.PhotoObjectIDs(ctx, photoID)
+	if err != nil {
+		return err
+	}
 	if err := s.store.HardDelete(ctx, photoID); err != nil {
 		return err
 	}
 	if p.AlbumID != "" {
 		s.publishDeleted(p)
 	}
-	if n, err := s.store.StorageKeyRefCount(ctx, p.StorageKey); err == nil && n == 0 {
-		keys := []string{p.StorageKey}
-		if p.ThumbKey != "" {
-			keys = append(keys, p.ThumbKey)
+	// Mark objects that no longer have any binding for garbage collection.
+	// The background worker removes the blobs from storage.
+	for _, oid := range objectIDs {
+		if n, err := s.store.ObjectRefCount(ctx, oid); err == nil && n == 0 {
+			_ = s.store.MarkObjectDeleting(ctx, oid)
 		}
-		if p.PreviewKey != "" {
-			keys = append(keys, p.PreviewKey)
-		}
-		_ = s.storage.Delete(ctx, keys...)
 	}
 	return nil
 }

backend/internal/photos/sqlite_helpers.go

@@ -0,0 +1,30 @@
+package photos
+
+import (
+	"time"
+
+	"shared-album/internal/sqliteutil"
+)
+
+func nullIfEmpty(s string) any {
+	if s == "" {
+		return nil
+	}
+	return s
+}
+
+func nullTime(t *time.Time) any {
+	if t == nil {
+		return nil
+	}
+	return sqliteutil.FormatTime(*t)
+}
+
+func nullFloat(f *float64) any {
+	if f == nil {
+		return nil
+	}
+	return *f
+}
+
+func nowUTC() time.Time { return time.Now().UTC() }

backend/internal/photos/sqlite_objects.go

@@ -0,0 +1,365 @@
+package photos
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"time"
+
+	"shared-album/internal/sqliteutil"
+)
+
+// CreateObject inserts a new object row in the pending state.
+func (s *SQLiteStore) CreateObject(ctx context.Context, o *Object) error {
+	if o.State == "" {
+		o.State = ObjectPending
+	}
+	var createdAt string
+	err := s.db.QueryRowContext(ctx,
+		`INSERT INTO objects (id, storage_key, mime_type, size, width, height, checksum, state)
+		 VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+		 RETURNING created_at`,
+		o.ID, o.StorageKey, o.MimeType, o.Size, o.Width, o.Height, o.Checksum, o.State).Scan(&createdAt)
+	if err != nil {
+		return err
+	}
+	o.CreatedAt = sqliteutil.ParseTime(createdAt)
+	return nil
+}
+
+// SetObjectState updates an object's lifecycle state.
+func (s *SQLiteStore) SetObjectState(ctx context.Context, id, state string) error {
+	res, err := s.db.ExecContext(ctx, `UPDATE objects SET state = $2 WHERE id = $1`, id, state)
+	if err != nil {
+		return err
+	}
+	if n, _ := res.RowsAffected(); n == 0 {
+		return ErrObjectNotFound
+	}
+	return nil
+}
+
+// ActivateObject marks an object ready after its bytes have been stored.
+func (s *SQLiteStore) ActivateObject(ctx context.Context, id string) error {
+	return s.SetObjectState(ctx, id, ObjectReady)
+}
+
+// MarkObjectDeleting marks an object as pending removal from storage.
+func (s *SQLiteStore) MarkObjectDeleting(ctx context.Context, id string) error {
+	return s.SetObjectState(ctx, id, ObjectDeleting)
+}
+
+// DeleteObjectRow permanently removes an object row (after its blob is gone).
+func (s *SQLiteStore) DeleteObjectRow(ctx context.Context, id string) error {
+	res, err := s.db.ExecContext(ctx, `DELETE FROM objects WHERE id = $1`, id)
+	if err != nil {
+		return err
+	}
+	if n, _ := res.RowsAffected(); n == 0 {
+		return ErrObjectNotFound
+	}
+	return nil
+}
+
+// BindObject attaches a ready object to a photo under the given role. The write
+// lock of the immediate transaction serializes it against garbage collection.
+func (s *SQLiteStore) BindObject(ctx context.Context, photoID, objectID, role string) error {
+	tx, err := s.db.BeginTx(ctx, nil)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = tx.Rollback() }()
+
+	var state string
+	if err := tx.QueryRowContext(ctx, `SELECT state FROM objects WHERE id = $1`, objectID).Scan(&state); err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return ErrObjectNotFound
+		}
+		return err
+	}
+	if state != ObjectReady {
+		return ErrObjectNotReady
+	}
+	if _, err := tx.ExecContext(ctx,
+		`INSERT INTO photo_objects (photo_id, object_id, role) VALUES ($1, $2, $3)
+		 ON CONFLICT (photo_id, role) DO UPDATE SET object_id = excluded.object_id`,
+		photoID, objectID, role); err != nil {
+		return err
+	}
+	return tx.Commit()
+}
+
+// PhotoObjectIDs returns the object ids currently bound to a photo.
+func (s *SQLiteStore) PhotoObjectIDs(ctx context.Context, photoID string) ([]string, error) {
+	rows, err := s.db.QueryContext(ctx, `SELECT object_id FROM photo_objects WHERE photo_id = $1`, photoID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var ids []string
+	for rows.Next() {
+		var id string
+		if err := rows.Scan(&id); err != nil {
+			return nil, err
+		}
+		ids = append(ids, id)
+	}
+	return ids, rows.Err()
+}
+
+// ObjectRefCount counts how many photo bindings reference an object.
+func (s *SQLiteStore) ObjectRefCount(ctx context.Context, objectID string) (int, error) {
+	var n int
+	err := s.db.QueryRowContext(ctx, `SELECT count(*) FROM photo_objects WHERE object_id = $1`, objectID).Scan(&n)
+	return n, err
+}
+
+// OriginalObject returns the original object bound to a photo.
+func (s *SQLiteStore) OriginalObject(ctx context.Context, photoID string) (*Object, error) {
+	var o Object
+	var createdAt string
+	err := s.db.QueryRowContext(ctx,
+		`SELECT o.id, o.storage_key, o.mime_type, o.size, o.width, o.height, o.checksum, o.state, o.created_at
+		 FROM photo_objects po JOIN objects o ON o.id = po.object_id
+		 WHERE po.photo_id = $1 AND po.role = $2`, photoID, RoleOriginal).
+		Scan(&o.ID, &o.StorageKey, &o.MimeType, &o.Size, &o.Width, &o.Height, &o.Checksum, &o.State, &createdAt)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, ErrObjectNotFound
+		}
+		return nil, err
+	}
+	o.CreatedAt = sqliteutil.ParseTime(createdAt)
+	return &o, nil
+}
+
+// PhotosByOriginalObject returns the ids of all photos bound to the given
+// original object, so generated variants can be shared between copies.
+func (s *SQLiteStore) PhotosByOriginalObject(ctx context.Context, originalObjectID string) ([]string, error) {
+	rows, err := s.db.QueryContext(ctx,
+		`SELECT photo_id FROM photo_objects WHERE object_id = $1 AND role = $2`, originalObjectID, RoleOriginal)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var ids []string
+	for rows.Next() {
+		var id string
+		if err := rows.Scan(&id); err != nil {
+			return nil, err
+		}
+		ids = append(ids, id)
+	}
+	return ids, rows.Err()
+}
+
+// ClaimGarbage claims collectible objects: ready objects with no bindings and
+// objects already marked deleting.
+func (s *SQLiteStore) ClaimGarbage(ctx context.Context, limit int) ([]Object, error) {
+	if limit <= 0 {
+		limit = 10
+	}
+	tx, err := s.db.BeginTx(ctx, nil)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = tx.Rollback() }()
+
+	rows, err := tx.QueryContext(ctx,
+		`SELECT o.id, o.storage_key FROM objects o
+		 WHERE o.state IN ('ready', 'deleting')
+		   AND NOT EXISTS (SELECT 1 FROM photo_objects po WHERE po.object_id = o.id)
+		 ORDER BY o.created_at
+		 LIMIT $1`, limit)
+	if err != nil {
+		return nil, err
+	}
+	objs, err := scanObjectKeys(rows)
+	if err != nil {
+		return nil, err
+	}
+	if len(objs) == 0 {
+		return nil, tx.Commit()
+	}
+	if err := markDeleting(ctx, tx, objs); err != nil {
+		return nil, err
+	}
+	if err := tx.Commit(); err != nil {
+		return nil, err
+	}
+	return objs, nil
+}
+
+// ClaimStalePending marks abandoned pending objects as deleting and returns them.
+func (s *SQLiteStore) ClaimStalePending(ctx context.Context, olderThan time.Duration, limit int) ([]Object, error) {
+	if limit <= 0 {
+		limit = 10
+	}
+	threshold := sqliteutil.FormatTime(time.Now().UTC().Add(-olderThan))
+	tx, err := s.db.BeginTx(ctx, nil)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = tx.Rollback() }()
+
+	rows, err := tx.QueryContext(ctx,
+		`SELECT id, storage_key FROM objects
+		 WHERE state = 'pending' AND created_at < $1
+		 ORDER BY created_at
+		 LIMIT $2`, threshold, limit)
+	if err != nil {
+		return nil, err
+	}
+	objs, err := scanObjectKeys(rows)
+	if err != nil {
+		return nil, err
+	}
+	if len(objs) == 0 {
+		return nil, tx.Commit()
+	}
+	if err := markDeleting(ctx, tx, objs); err != nil {
+		return nil, err
+	}
+	if err := tx.Commit(); err != nil {
+		return nil, err
+	}
+	return objs, nil
+}
+
+// ClaimVariantJobs leases due variant jobs and returns their photo ids.
+func (s *SQLiteStore) ClaimVariantJobs(ctx context.Context, limit int, lease time.Duration) ([]string, error) {
+	if limit <= 0 {
+		limit = 10
+	}
+	now := sqliteutil.FormatTime(time.Now().UTC())
+	next := sqliteutil.FormatTime(time.Now().UTC().Add(lease))
+	tx, err := s.db.BeginTx(ctx, nil)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = tx.Rollback() }()
+
+	rows, err := tx.QueryContext(ctx,
+		`SELECT photo_id FROM variant_jobs
+		 WHERE next_attempt_at <= $1
+		 ORDER BY next_attempt_at
+		 LIMIT $2`, now, limit)
+	if err != nil {
+		return nil, err
+	}
+	var ids []string
+	for rows.Next() {
+		var id string
+		if err := rows.Scan(&id); err != nil {
+			rows.Close()
+			return nil, err
+		}
+		ids = append(ids, id)
+	}
+	rows.Close()
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	if len(ids) == 0 {
+		return nil, tx.Commit()
+	}
+	args := make([]any, 0, len(ids)+1)
+	args = append(args, next)
+	for _, id := range ids {
+		args = append(args, id)
+	}
+	if _, err := tx.ExecContext(ctx,
+		`UPDATE variant_jobs SET next_attempt_at = $1 WHERE photo_id IN (`+sqliteutil.Placeholders(2, len(ids))+`)`,
+		args...); err != nil {
+		return nil, err
+	}
+	if err := tx.Commit(); err != nil {
+		return nil, err
+	}
+	return ids, nil
+}
+
+// CompleteVariantJob removes a finished job.
+func (s *SQLiteStore) CompleteVariantJob(ctx context.Context, photoID string) error {
+	_, err := s.db.ExecContext(ctx, `DELETE FROM variant_jobs WHERE photo_id = $1`, photoID)
+	return err
+}
+
+// FailVariantJob records a failure and schedules a retry with exponential
+// backoff, abandoning the job after maxAttempts.
+func (s *SQLiteStore) FailVariantJob(ctx context.Context, photoID, errMsg string, maxAttempts int) error {
+	tx, err := s.db.BeginTx(ctx, nil)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = tx.Rollback() }()
+
+	var attempts int
+	err = tx.QueryRowContext(ctx, `SELECT attempts FROM variant_jobs WHERE photo_id = $1`, photoID).Scan(&attempts)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return tx.Commit()
+		}
+		return err
+	}
+	newAttempts := attempts + 1
+	if maxAttempts > 0 && newAttempts >= maxAttempts {
+		if _, err := tx.ExecContext(ctx, `DELETE FROM variant_jobs WHERE photo_id = $1`, photoID); err != nil {
+			return err
+		}
+	} else {
+		secs := 10 * (1 << attempts)
+		if secs > 300 {
+			secs = 300
+		}
+		next := sqliteutil.FormatTime(time.Now().UTC().Add(time.Duration(secs) * time.Second))
+		if _, err := tx.ExecContext(ctx,
+			`UPDATE variant_jobs SET attempts = $2, next_attempt_at = $3, last_error = $4 WHERE photo_id = $1`,
+			photoID, newAttempts, next, errMsg); err != nil {
+			return err
+		}
+	}
+	return tx.Commit()
+}
+
+func scanObjectKeys(rows *sql.Rows) ([]Object, error) {
+	var objs []Object
+	for rows.Next() {
+		var o Object
+		if err := rows.Scan(&o.ID, &o.StorageKey); err != nil {
+			rows.Close()
+			return nil, err
+		}
+		objs = append(objs, o)
+	}
+	rows.Close()
+	return objs, rows.Err()
+}
+
+func markDeleting(ctx context.Context, tx *sql.Tx, objs []Object) error {
+	args := make([]any, len(objs))
+	for i, o := range objs {
+		args[i] = o.ID
+	}
+	_, err := tx.ExecContext(ctx,
+		`UPDATE objects SET state = 'deleting' WHERE id IN (`+sqliteutil.Placeholders(1, len(objs))+`)`, args...)
+	return err
+}
+
+// AllStorageKeys returns every key registered in the object journal.
+func (s *SQLiteStore) AllStorageKeys(ctx context.Context) ([]string, error) {
+	rows, err := s.db.QueryContext(ctx, `SELECT storage_key FROM objects`)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var keys []string
+	for rows.Next() {
+		var k string
+		if err := rows.Scan(&k); err != nil {
+			return nil, err
+		}
+		keys = append(keys, k)
+	}
+	return keys, rows.Err()
+}

backend/internal/photos/sqlite_store.go

@@ -0,0 +1,470 @@
+package photos
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"errors"
+	"strings"
+
+	"shared-album/internal/auth"
+	"shared-album/internal/models"
+	"shared-album/internal/sqliteutil"
+)
+
+// SQLiteStore is the SQLite implementation of Repository.
+type SQLiteStore struct {
+	db *sql.DB
+}
+
+func NewSQLiteStore(db *sql.DB) *SQLiteStore { return &SQLiteStore{db: db} }
+
+const sqlitePhotoColumns = `p.id, COALESCE(p.album_id, ''), p.uploader_id,
+	COALESCE(o_o.storage_key, ''),
+	COALESCE(o_t.storage_key, ''),
+	COALESCE(o_p.storage_key, ''),
+	p.original_filename, COALESCE(o_o.size, 0), COALESCE(o_o.width, 0), COALESCE(o_o.height, 0), COALESCE(o_o.mime_type, ''),
+	p.taken_at, p.latitude, p.longitude, COALESCE(p.caption, ''), p.created_at,
+	u.id, u.name, COALESCE(u.avatar_url, ''),
+	(SELECT count(*) FROM likes l WHERE l.photo_id = p.id),
+	(SELECT count(*) FROM comments c WHERE c.photo_id = p.id),
+	EXISTS(SELECT 1 FROM likes l WHERE l.photo_id = p.id AND l.user_id = $2),
+	COALESCE(p.exif, '{}'), p.deleted_at,
+	COALESCE((SELECT json_group_array(json_object('id', t.id, 'name', t.name))
+		FROM (SELECT t.id, t.name FROM photo_tags pt JOIN tags t ON t.id = pt.tag_id
+		      WHERE pt.photo_id = p.id AND t.user_id = $2
+		      ORDER BY lower(t.name)) t), '[]')`
+
+const sqlitePhotoJoins = `
+	LEFT JOIN photo_objects po_o ON po_o.photo_id = p.id AND po_o.role = 'original'
+	LEFT JOIN objects o_o ON o_o.id = po_o.object_id
+	LEFT JOIN photo_objects po_t ON po_t.photo_id = p.id AND po_t.role = 'thumb'
+	LEFT JOIN objects o_t ON o_t.id = po_t.object_id
+	LEFT JOIN photo_objects po_p ON po_p.photo_id = p.id AND po_p.role = 'preview'
+	LEFT JOIN objects o_p ON o_p.id = po_p.object_id`
+
+func scanSQLitePhoto(scan func(...any) error) (*models.Photo, error) {
+	var p models.Photo
+	var exifText, tagsText, createdAt string
+	var takenAt, deletedAt sql.NullString
+	var lat, long sql.NullFloat64
+	var liked int
+	if err := scan(&p.ID, &p.AlbumID, &p.UploaderID, &p.StorageKey,
+		&p.ThumbKey, &p.PreviewKey,
+		&p.OriginalFilename, &p.Size, &p.Width, &p.Height, &p.MimeType,
+		&takenAt, &lat, &long, &p.Caption, &createdAt,
+		&p.Uploader.ID, &p.Uploader.Name, &p.Uploader.AvatarURL,
+		&p.LikesCount, &p.CommentsCount, &liked, &exifText, &deletedAt, &tagsText); err != nil {
+		return nil, err
+	}
+	p.TakenAt = sqliteutil.ParseNullTime(takenAt)
+	if lat.Valid {
+		p.Latitude = &lat.Float64
+	}
+	if long.Valid {
+		p.Longitude = &long.Float64
+	}
+	p.CreatedAt = sqliteutil.ParseTime(createdAt)
+	p.DeletedAt = sqliteutil.ParseNullTime(deletedAt)
+	p.LikedByMe = liked != 0
+	setExif(&p, exifText)
+	setTags(&p, tagsText)
+	return &p, nil
+}
+
+func (s *SQLiteStore) CreateWithOriginal(ctx context.Context, p *models.Photo, obj *Object) error {
+	exifJSON, err := json.Marshal(p.EXIF)
+	if err != nil || len(exifJSON) == 0 {
+		exifJSON = []byte("{}")
+	}
+	tx, err := s.db.BeginTx(ctx, nil)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = tx.Rollback() }()
+
+	if _, err := tx.ExecContext(ctx,
+		`INSERT INTO objects (id, storage_key, mime_type, size, width, height, checksum, state)
+		 VALUES ($1, $2, $3, $4, $5, $6, $7, $8)`,
+		obj.ID, obj.StorageKey, obj.MimeType, obj.Size, obj.Width, obj.Height, obj.Checksum, ObjectPending); err != nil {
+		return err
+	}
+	var createdAt string
+	if err := tx.QueryRowContext(ctx,
+		`INSERT INTO photos (id, album_id, uploader_id, original_filename, taken_at, latitude, longitude, caption, exif)
+		 VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)
+		 RETURNING created_at`,
+		p.ID, nullIfEmpty(p.AlbumID), p.UploaderID, p.OriginalFilename,
+		nullTime(p.TakenAt), nullFloat(p.Latitude), nullFloat(p.Longitude), p.Caption, string(exifJSON),
+	).Scan(&createdAt); err != nil {
+		return err
+	}
+	p.CreatedAt = sqliteutil.ParseTime(createdAt)
+	if _, err := tx.ExecContext(ctx,
+		`INSERT INTO photo_objects (photo_id, object_id, role) VALUES ($1, $2, $3)`,
+		p.ID, obj.ID, RoleOriginal); err != nil {
+		return err
+	}
+	if _, err := tx.ExecContext(ctx,
+		`INSERT INTO variant_jobs (photo_id) VALUES ($1) ON CONFLICT (photo_id) DO NOTHING`, p.ID); err != nil {
+		return err
+	}
+	return tx.Commit()
+}
+
+func (s *SQLiteStore) DeleteUpload(ctx context.Context, photoID, objectID string) error {
+	tx, err := s.db.BeginTx(ctx, nil)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = tx.Rollback() }()
+	if _, err := tx.ExecContext(ctx, `DELETE FROM photos WHERE id = $1`, photoID); err != nil {
+		return err
+	}
+	if _, err := tx.ExecContext(ctx, `DELETE FROM objects WHERE id = $1`, objectID); err != nil {
+		return err
+	}
+	return tx.Commit()
+}
+
+func (s *SQLiteStore) GetByID(ctx context.Context, id, viewerID string) (*models.Photo, error) {
+	row := s.db.QueryRowContext(ctx,
+		`SELECT `+sqlitePhotoColumns+`
+		 FROM photos p JOIN users u ON u.id = p.uploader_id`+sqlitePhotoJoins+`
+		 WHERE p.id = $1`, id, viewerID)
+	p, err := scanSQLitePhoto(row.Scan)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, ErrNotFound
+		}
+		return nil, err
+	}
+	return p, nil
+}
+
+func (s *SQLiteStore) List(ctx context.Context, in ListParams) ([]models.Photo, error) {
+	if in.Limit <= 0 || in.Limit > 100 {
+		in.Limit = 50
+	}
+	var since any
+	if in.Since != nil {
+		since = sqliteutil.FormatTime(*in.Since)
+	}
+	rows, err := s.db.QueryContext(ctx,
+		`SELECT `+sqlitePhotoColumns+`
+		 FROM photos p JOIN users u ON u.id = p.uploader_id`+sqlitePhotoJoins+`
+		 WHERE p.album_id = $1
+		   AND p.deleted_at IS NULL
+		   AND ($3 = '' OR (p.created_at, p.id) < (SELECT created_at, id FROM photos WHERE id = $3))
+		   AND ($4 IS NULL OR p.created_at > $4)
+		 ORDER BY p.created_at DESC, p.id DESC
+		 LIMIT $5`,
+		in.AlbumID, in.Viewer, in.Cursor, since, in.Limit)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	out := []models.Photo{}
+	for rows.Next() {
+		p, err := scanSQLitePhoto(rows.Scan)
+		if err != nil {
+			return nil, err
+		}
+		out = append(out, *p)
+	}
+	return out, rows.Err()
+}
+
+func (s *SQLiteStore) SetDeleted(ctx context.Context, id string, deleted bool) error {
+	var res sql.Result
+	var err error
+	if deleted {
+		res, err = s.db.ExecContext(ctx,
+			`UPDATE photos SET deleted_at = $2 WHERE id = $1 AND deleted_at IS NULL`,
+			id, sqliteutil.FormatTime(nowUTC()))
+	} else {
+		res, err = s.db.ExecContext(ctx, `UPDATE photos SET deleted_at = NULL WHERE id = $1`, id)
+	}
+	if err != nil {
+		return err
+	}
+	if n, _ := res.RowsAffected(); n == 0 {
+		return ErrNotFound
+	}
+	return nil
+}
+
+func (s *SQLiteStore) UpdateAlbum(ctx context.Context, id, albumID string) error {
+	res, err := s.db.ExecContext(ctx,
+		`UPDATE photos SET album_id = $2 WHERE id = $1 AND deleted_at IS NULL`, id, albumID)
+	if err != nil {
+		return err
+	}
+	if n, _ := res.RowsAffected(); n == 0 {
+		return ErrNotFound
+	}
+	return nil
+}
+
+func (s *SQLiteStore) Clone(ctx context.Context, src *models.Photo, albumID, uploaderID, id string) error {
+	exifJSON, err := json.Marshal(src.EXIF)
+	if err != nil || len(exifJSON) == 0 {
+		exifJSON = []byte("{}")
+	}
+	tx, err := s.db.BeginTx(ctx, nil)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = tx.Rollback() }()
+
+	if _, err := tx.ExecContext(ctx,
+		`INSERT INTO photos (id, album_id, uploader_id, original_filename, taken_at, latitude, longitude, caption, exif)
+		 VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)`,
+		id, nullIfEmpty(albumID), uploaderID, src.OriginalFilename,
+		nullTime(src.TakenAt), nullFloat(src.Latitude), nullFloat(src.Longitude), src.Caption, string(exifJSON)); err != nil {
+		return err
+	}
+	if _, err := tx.ExecContext(ctx,
+		`INSERT INTO photo_objects (photo_id, object_id, role)
+		 SELECT $1, object_id, role FROM photo_objects WHERE photo_id = $2`,
+		id, src.ID); err != nil {
+		return err
+	}
+	return tx.Commit()
+}
+
+func (s *SQLiteStore) HardDelete(ctx context.Context, id string) error {
+	res, err := s.db.ExecContext(ctx, `DELETE FROM photos WHERE id = $1`, id)
+	if err != nil {
+		return err
+	}
+	if n, _ := res.RowsAffected(); n == 0 {
+		return ErrNotFound
+	}
+	return nil
+}
+
+func (s *SQLiteStore) ListTrash(ctx context.Context, userID string) ([]models.Photo, error) {
+	rows, err := s.db.QueryContext(ctx,
+		`SELECT `+sqlitePhotoColumns+`, COALESCE(a.title, '')
+		 FROM photos p
+		 JOIN users u ON u.id = p.uploader_id
+		 LEFT JOIN albums a ON a.id = p.album_id`+sqlitePhotoJoins+`
+		 WHERE p.deleted_at IS NOT NULL
+		   AND (
+		   	(a.id IS NOT NULL AND (a.owner_id = $1 OR EXISTS(
+		   		SELECT 1 FROM album_members m WHERE m.album_id = a.id AND m.user_id = $1)))
+		   	OR (p.album_id IS NULL AND p.uploader_id = $1)
+		   )
+		 ORDER BY p.deleted_at DESC
+		 LIMIT 200`,
+		userID, userID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	out := []models.Photo{}
+	for rows.Next() {
+		var p models.Photo
+		var exifText, tagsText, createdAt, albumTitle string
+		var takenAt, deletedAt sql.NullString
+		var lat, long sql.NullFloat64
+		var liked int
+		if err := rows.Scan(&p.ID, &p.AlbumID, &p.UploaderID, &p.StorageKey,
+			&p.ThumbKey, &p.PreviewKey,
+			&p.OriginalFilename, &p.Size, &p.Width, &p.Height, &p.MimeType,
+			&takenAt, &lat, &long, &p.Caption, &createdAt,
+			&p.Uploader.ID, &p.Uploader.Name, &p.Uploader.AvatarURL,
+			&p.LikesCount, &p.CommentsCount, &liked, &exifText, &deletedAt, &albumTitle, &tagsText); err != nil {
+			return nil, err
+		}
+		p.TakenAt = sqliteutil.ParseNullTime(takenAt)
+		if lat.Valid {
+			p.Latitude = &lat.Float64
+		}
+		if long.Valid {
+			p.Longitude = &long.Float64
+		}
+		p.CreatedAt = sqliteutil.ParseTime(createdAt)
+		p.DeletedAt = sqliteutil.ParseNullTime(deletedAt)
+		p.AlbumTitle = albumTitle
+		p.LikedByMe = liked != 0
+		setExif(&p, exifText)
+		setTags(&p, tagsText)
+		out = append(out, p)
+	}
+	return out, rows.Err()
+}
+
+func (s *SQLiteStore) TrashCount(ctx context.Context, userID string) (int, error) {
+	var n int
+	err := s.db.QueryRowContext(ctx,
+		`SELECT count(*) FROM photos p
+		 LEFT JOIN albums a ON a.id = p.album_id
+		 WHERE p.deleted_at IS NOT NULL
+		   AND (
+		   	(a.id IS NOT NULL AND (a.owner_id = $1 OR EXISTS(
+		   		SELECT 1 FROM album_members m WHERE m.album_id = a.id AND m.user_id = $1)))
+		   	OR (p.album_id IS NULL AND p.uploader_id = $1)
+		   )`, userID).Scan(&n)
+	return n, err
+}
+
+func (s *SQLiteStore) RestoreToAlbum(ctx context.Context, id, albumID string) error {
+	res, err := s.db.ExecContext(ctx,
+		`UPDATE photos SET album_id = $2, deleted_at = NULL WHERE id = $1`, id, albumID)
+	if err != nil {
+		return err
+	}
+	if n, _ := res.RowsAffected(); n == 0 {
+		return ErrNotFound
+	}
+	return nil
+}
+
+func (s *SQLiteStore) AlbumExists(ctx context.Context, albumID string) (bool, error) {
+	var ok int
+	err := s.db.QueryRowContext(ctx, `SELECT EXISTS(SELECT 1 FROM albums WHERE id = $1)`, albumID).Scan(&ok)
+	return ok != 0, err
+}
+
+func (s *SQLiteStore) ListTags(ctx context.Context, userID, q string) ([]models.Tag, error) {
+	rows, err := s.db.QueryContext(ctx,
+		`SELECT id, name FROM tags
+		 WHERE user_id = $1 AND ($2 = '' OR name LIKE '%' || $2 || '%')
+		 ORDER BY lower(name) LIMIT 50`, userID, q)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	out := []models.Tag{}
+	for rows.Next() {
+		var t models.Tag
+		if err := rows.Scan(&t.ID, &t.Name); err != nil {
+			return nil, err
+		}
+		out = append(out, t)
+	}
+	return out, rows.Err()
+}
+
+func (s *SQLiteStore) EnsureTag(ctx context.Context, userID, name string) (*models.Tag, error) {
+	name = strings.TrimSpace(name)
+	if name == "" || len(name) > 64 {
+		return nil, ErrNotFound
+	}
+	var t models.Tag
+	err := s.db.QueryRowContext(ctx,
+		`SELECT id, name FROM tags WHERE user_id = $1 AND lower(name) = lower($2)`, userID, name).
+		Scan(&t.ID, &t.Name)
+	if err == nil {
+		return &t, nil
+	}
+	if !errors.Is(err, sql.ErrNoRows) {
+		return nil, err
+	}
+	id := auth.NewID()
+	err = s.db.QueryRowContext(ctx,
+		`INSERT INTO tags (id, user_id, name) VALUES ($1, $2, $3) RETURNING id, name`, id, userID, name).
+		Scan(&t.ID, &t.Name)
+	if err != nil {
+		if e2 := s.db.QueryRowContext(ctx,
+			`SELECT id, name FROM tags WHERE user_id = $1 AND lower(name) = lower($2)`, userID, name).
+			Scan(&t.ID, &t.Name); e2 == nil {
+			return &t, nil
+		}
+		return nil, err
+	}
+	return &t, nil
+}
+
+func (s *SQLiteStore) AttachTag(ctx context.Context, photoID, tagID string) error {
+	_, err := s.db.ExecContext(ctx,
+		`INSERT INTO photo_tags (photo_id, tag_id) VALUES ($1, $2) ON CONFLICT DO NOTHING`, photoID, tagID)
+	return err
+}
+
+func (s *SQLiteStore) DetachTag(ctx context.Context, photoID, tagID string) error {
+	_, err := s.db.ExecContext(ctx,
+		`DELETE FROM photo_tags WHERE photo_id = $1 AND tag_id = $2`, photoID, tagID)
+	return err
+}
+
+func (s *SQLiteStore) TagOwnedBy(ctx context.Context, tagID, userID string) (bool, error) {
+	var ok int
+	err := s.db.QueryRowContext(ctx,
+		`SELECT EXISTS(SELECT 1 FROM tags WHERE id = $1 AND user_id = $2)`, tagID, userID).Scan(&ok)
+	return ok != 0, err
+}
+
+func (s *SQLiteStore) SetCoverIfEmpty(ctx context.Context, albumID, photoID string) {
+	_, _ = s.db.ExecContext(ctx,
+		`UPDATE albums SET cover_photo_id = $2 WHERE id = $1 AND cover_photo_id IS NULL`,
+		albumID, photoID)
+}
+
+func (s *SQLiteStore) UpdateFilename(ctx context.Context, id, filename string) error {
+	res, err := s.db.ExecContext(ctx, `UPDATE photos SET original_filename = $2 WHERE id = $1`, id, filename)
+	if err != nil {
+		return err
+	}
+	if n, _ := res.RowsAffected(); n == 0 {
+		return ErrNotFound
+	}
+	return nil
+}
+
+// BackfillEXIF mirrors the PostgreSQL implementation, reading the original blob
+// of every photo with empty exif.
+func (s *SQLiteStore) BackfillEXIF(ctx context.Context, fetch func(context.Context, string) ([]byte, error)) (int, error) {
+	rows, err := s.db.QueryContext(ctx,
+		`SELECT p.id, o.storage_key
+		 FROM photos p
+		 JOIN photo_objects po ON po.photo_id = p.id AND po.role = 'original'
+		 JOIN objects o ON o.id = po.object_id
+		 WHERE p.exif IS NULL OR p.exif = '{}'
+		 ORDER BY p.created_at`)
+	if err != nil {
+		return 0, err
+	}
+	var pending []backfillRow
+	for rows.Next() {
+		var r backfillRow
+		if err := rows.Scan(&r.ID, &r.StorageKey); err != nil {
+			rows.Close()
+			return 0, err
+		}
+		pending = append(pending, r)
+	}
+	rows.Close()
+	if err := rows.Err(); err != nil {
+		return 0, err
+	}
+
+	updated := 0
+	for _, r := range pending {
+		data, err := fetch(ctx, r.StorageKey)
+		if err != nil {
+			continue
+		}
+		meta := extractEXIF(data)
+		if len(meta.Attributes) == 0 && meta.TakenAt == nil && meta.Latitude == nil && meta.Longitude == nil {
+			continue
+		}
+		attrs, err := json.Marshal(meta.Attributes)
+		if err != nil || len(attrs) == 0 {
+			attrs = []byte("{}")
+		}
+		if _, err := s.db.ExecContext(ctx,
+			`UPDATE photos SET exif = $2,
+				taken_at = COALESCE(taken_at, $3),
+				latitude = COALESCE(latitude, $4),
+				longitude = COALESCE(longitude, $5)
+			 WHERE id = $1`,
+			r.ID, string(attrs), nullTime(meta.TakenAt), nullFloat(meta.Latitude), nullFloat(meta.Longitude)); err != nil {
+			continue
+		}
+		updated++
+	}
+	return updated, nil
+}

backend/internal/photos/store.go

@@ -23,9 +23,14 @@ type Store struct {
 
 func NewStore(pool *pgxpool.Pool) *Store { return &Store{pool: pool} }
 
-const photoColumns = `p.id, COALESCE(p.album_id, ''), p.uploader_id, p.storage_key,
-	COALESCE(p.thumb_key, ''), COALESCE(p.preview_key, ''),
-	p.original_filename, p.size, p.width, p.height, p.mime_type,
+// photoColumns selects photo rows together with the keys and physical facts of
+// their bound objects (original, thumb, preview) and the original's size,
+// dimensions and mime type.
+const photoColumns = `p.id, COALESCE(p.album_id, ''), p.uploader_id,
+	COALESCE(o_o.storage_key, ''),
+	COALESCE(o_t.storage_key, ''),
+	COALESCE(o_p.storage_key, ''),
+	p.original_filename, COALESCE(o_o.size, 0), COALESCE(o_o.width, 0), COALESCE(o_o.height, 0), COALESCE(o_o.mime_type, ''),
 	p.taken_at, p.latitude, p.longitude, COALESCE(p.caption, ''), p.created_at,
 	u.id, u.name, COALESCE(u.avatar_url, ''),
 	(SELECT count(*) FROM likes l WHERE l.photo_id = p.id),
@@ -36,6 +41,14 @@ const photoColumns = `p.id, COALESCE(p.album_id, ''), p.uploader_id, p.storage_k
 		FROM photo_tags pt JOIN tags t ON t.id = pt.tag_id
 		WHERE pt.photo_id = p.id AND t.user_id = $2), '[]')::text`
 
+const photoJoins = `
+	LEFT JOIN photo_objects po_o ON po_o.photo_id = p.id AND po_o.role = 'original'
+	LEFT JOIN objects o_o ON o_o.id = po_o.object_id
+	LEFT JOIN photo_objects po_t ON po_t.photo_id = p.id AND po_t.role = 'thumb'
+	LEFT JOIN objects o_t ON o_t.id = po_t.object_id
+	LEFT JOIN photo_objects po_p ON po_p.photo_id = p.id AND po_p.role = 'preview'
+	LEFT JOIN objects o_p ON o_p.id = po_p.object_id`
+
 func scanPhoto(row pgx.Row) (*models.Photo, error) {
 	var p models.Photo
 	var exifText, tagsText string
@@ -76,31 +89,68 @@ func setExif(p *models.Photo, raw string) {
 	}
 }
 
-func (s *Store) Create(ctx context.Context, p *models.Photo) error {
+// CreateWithOriginal records a new photo together with its pending original
+// object, the original binding and a variant job — all in one transaction. The
+// caller stores the bytes and then activates the object. The metadata layer is
+// the ledger of record; the storage layer follows.
+func (s *Store) CreateWithOriginal(ctx context.Context, p *models.Photo, obj *Object) error {
 	exifJSON, err := json.Marshal(p.EXIF)
 	if err != nil || len(exifJSON) == 0 {
 		exifJSON = []byte("{}")
 	}
-	return s.pool.QueryRow(ctx,
-		`INSERT INTO photos (id, album_id, uploader_id, storage_key, original_filename,
-			size, width, height, mime_type, taken_at, latitude, longitude, caption, exif)
-		 VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12,$13,$14::jsonb)
+	tx, err := s.pool.Begin(ctx)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = tx.Rollback(ctx) }()
+
+	if _, err := tx.Exec(ctx,
+		`INSERT INTO objects (id, storage_key, mime_type, size, width, height, checksum, state)
+		 VALUES ($1, $2, $3, $4, $5, $6, $7, $8)`,
+		obj.ID, obj.StorageKey, obj.MimeType, obj.Size, obj.Width, obj.Height, obj.Checksum, ObjectPending); err != nil {
+		return err
+	}
+	if err := tx.QueryRow(ctx,
+		`INSERT INTO photos (id, album_id, uploader_id, original_filename, taken_at, latitude, longitude, caption, exif)
+		 VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9::jsonb)
 		 RETURNING created_at`,
-		p.ID, p.AlbumID, p.UploaderID, p.StorageKey, p.OriginalFilename,
-		p.Size, p.Width, p.Height, p.MimeType, p.TakenAt, p.Latitude, p.Longitude, p.Caption, string(exifJSON),
-	).Scan(&p.CreatedAt)
+		p.ID, p.AlbumID, p.UploaderID, p.OriginalFilename, p.TakenAt, p.Latitude, p.Longitude, p.Caption, string(exifJSON),
+	).Scan(&p.CreatedAt); err != nil {
+		return err
+	}
+	if _, err := tx.Exec(ctx,
+		`INSERT INTO photo_objects (photo_id, object_id, role) VALUES ($1, $2, $3)`,
+		p.ID, obj.ID, RoleOriginal); err != nil {
+		return err
+	}
+	if _, err := tx.Exec(ctx,
+		`INSERT INTO variant_jobs (photo_id) VALUES ($1) ON CONFLICT (photo_id) DO NOTHING`, p.ID); err != nil {
+		return err
+	}
+	return tx.Commit(ctx)
 }
 
-func (s *Store) SetVariants(ctx context.Context, id, thumbKey, previewKey string) error {
-	_, err := s.pool.Exec(ctx,
-		`UPDATE photos SET thumb_key = $2, preview_key = $3 WHERE id = $1`, id, thumbKey, previewKey)
+// DeleteUpload rolls back a failed upload: the photo (and its bindings and job)
+// plus the pending object row are removed.
+func (s *Store) DeleteUpload(ctx context.Context, photoID, objectID string) error {
+	tx, err := s.pool.Begin(ctx)
+	if err != nil {
 		return err
+	}
+	defer func() { _ = tx.Rollback(ctx) }()
+	if _, err := tx.Exec(ctx, `DELETE FROM photos WHERE id = $1`, photoID); err != nil {
+		return err
+	}
+	if _, err := tx.Exec(ctx, `DELETE FROM objects WHERE id = $1`, objectID); err != nil {
+		return err
+	}
+	return tx.Commit(ctx)
 }
 
 func (s *Store) GetByID(ctx context.Context, id, viewerID string) (*models.Photo, error) {
 	return scanPhoto(s.pool.QueryRow(ctx,
 		`SELECT `+photoColumns+`
-		 FROM photos p JOIN users u ON u.id = p.uploader_id
+		 FROM photos p JOIN users u ON u.id = p.uploader_id`+photoJoins+`
 		 WHERE p.id = $1`, id, viewerID))
 }
 
@@ -118,7 +168,7 @@ func (s *Store) List(ctx context.Context, in ListParams) ([]models.Photo, error)
 	}
 	rows, err := s.pool.Query(ctx,
 		`SELECT `+photoColumns+`
-		 FROM photos p JOIN users u ON u.id = p.uploader_id
+		 FROM photos p JOIN users u ON u.id = p.uploader_id`+photoJoins+`
 		 WHERE p.album_id = $1
 		   AND p.deleted_at IS NULL
 		   AND ($3 = '' OR (p.created_at, p.id) < (SELECT created_at, id FROM photos WHERE id = $3))
@@ -181,30 +231,36 @@ func (s *Store) UpdateAlbum(ctx context.Context, id, albumID string) error {
 	return nil
 }
 
-// Clone creates a new photo row that references the same stored objects as src.
+// Clone creates a new photo row in albumID that references the same objects as
+// src. No storage operation is performed: the clone shares the physical files.
 func (s *Store) Clone(ctx context.Context, src *models.Photo, albumID, uploaderID, id string) error {
 	exifJSON, err := json.Marshal(src.EXIF)
 	if err != nil || len(exifJSON) == 0 {
 		exifJSON = []byte("{}")
 	}
-	_, err = s.pool.Exec(ctx,
-		`INSERT INTO photos (id, album_id, uploader_id, storage_key, thumb_key, preview_key,
-			original_filename, size, width, height, mime_type, taken_at, latitude, longitude, caption, exif)
-		 VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12,$13,$14,$15,$16::jsonb)`,
-		id, albumID, uploaderID, src.StorageKey, nullIfEmpty(src.ThumbKey), nullIfEmpty(src.PreviewKey),
-		src.OriginalFilename, src.Size, src.Width, src.Height, src.MimeType,
-		src.TakenAt, src.Latitude, src.Longitude, src.Caption, string(exifJSON))
+	tx, err := s.pool.Begin(ctx)
+	if err != nil {
 		return err
+	}
+	defer func() { _ = tx.Rollback(ctx) }()
+
+	if _, err := tx.Exec(ctx,
+		`INSERT INTO photos (id, album_id, uploader_id, original_filename, taken_at, latitude, longitude, caption, exif)
+		 VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9::jsonb)`,
+		id, albumID, uploaderID, src.OriginalFilename, src.TakenAt, src.Latitude, src.Longitude, src.Caption, string(exifJSON)); err != nil {
+		return err
+	}
+	if _, err := tx.Exec(ctx,
+		`INSERT INTO photo_objects (photo_id, object_id, role)
+		 SELECT $1, object_id, role FROM photo_objects WHERE photo_id = $2`,
+		id, src.ID); err != nil {
+		return err
+	}
+	return tx.Commit(ctx)
 }
 
-// StorageKeyRefCount counts photo rows (any state) referencing the stored object.
-func (s *Store) StorageKeyRefCount(ctx context.Context, storageKey string) (int, error) {
-	var n int
-	err := s.pool.QueryRow(ctx, `SELECT count(*) FROM photos WHERE storage_key = $1`, storageKey).Scan(&n)
-	return n, err
-}
-
-// HardDelete permanently removes the photo row.
+// HardDelete permanently removes the photo row. Bound objects are not touched
+// here; the caller marks orphaned objects for collection.
 func (s *Store) HardDelete(ctx context.Context, id string) error {
 	tag, err := s.pool.Exec(ctx, `DELETE FROM photos WHERE id = $1`, id)
 	if err != nil {
@@ -223,7 +279,7 @@ func (s *Store) ListTrash(ctx context.Context, userID string) ([]models.Photo, e
 		`SELECT `+photoColumns+`, COALESCE(a.title, '')
 		 FROM photos p
 		 JOIN users u ON u.id = p.uploader_id
-		 LEFT JOIN albums a ON a.id = p.album_id
+		 LEFT JOIN albums a ON a.id = p.album_id`+photoJoins+`
 		 WHERE p.deleted_at IS NOT NULL
 		   AND (
 		   	(a.id IS NOT NULL AND (a.owner_id = $1 OR EXISTS(
@@ -362,13 +418,6 @@ func (s *Store) TagOwnedBy(ctx context.Context, tagID, userID string) (bool, err
 	return ok, err
 }
 
-func nullIfEmpty(s string) *string {
-	if s == "" {
-		return nil
-	}
-	return &s
-}
-
 func (s *Store) SetCoverIfEmpty(ctx context.Context, albumID, photoID string) {
 	_, _ = s.pool.Exec(ctx,
 		`UPDATE albums SET cover_photo_id = $2 WHERE id = $1 AND cover_photo_id IS NULL`,
@@ -391,11 +440,16 @@ type backfillRow struct {
 	StorageKey string
 }
 
+// BackfillEXIF re-reads the original object of every photo with empty exif and
+// fills the exif/geo fields on the photo.
 func (s *Store) BackfillEXIF(ctx context.Context, fetch func(context.Context, string) ([]byte, error)) (int, error) {
 	rows, err := s.pool.Query(ctx,
-		`SELECT id, storage_key FROM photos
-		 WHERE exif IS NULL OR exif = '{}'::jsonb
-		 ORDER BY created_at`)
+		`SELECT p.id, o.storage_key
+		 FROM photos p
+		 JOIN photo_objects po ON po.photo_id = p.id AND po.role = 'original'
+		 JOIN objects o ON o.id = po.object_id
+		 WHERE p.exif IS NULL OR p.exif = '{}'::jsonb
+		 ORDER BY p.created_at`)
 	if err != nil {
 		return 0, err
 	}

backend/internal/photos/upload_test.go

@@ -0,0 +1,70 @@
+package photos
+
+import (
+	"context"
+	"strings"
+	"testing"
+)
+
+func TestUploadCreatesLedgerAndAlbumFreeKey(t *testing.T) {
+	pool := testPool(t)
+	ctx := context.Background()
+	svc, cl := newTestService(t, pool)
+	user := createUser(t, ctx, pool)
+	album := createAlbum(t, ctx, pool, user)
+
+	p, err := svc.Upload(ctx, UploadInput{
+		AlbumID:  album,
+		UserID:   user,
+		Filename: "photo.png",
+		MimeType: "image/png",
+		Data:     makePNG(t),
+	})
+	if err != nil {
+		t.Fatalf("upload: %v", err)
+	}
+	t.Cleanup(func() { cleanupPhoto(t, ctx, pool, cl, p.ID) })
+
+	if !strings.HasPrefix(p.StorageKey, "objects/") {
+		t.Fatalf("storage key %q is not an object key", p.StorageKey)
+	}
+	if strings.Contains(p.StorageKey, album) {
+		t.Fatalf("storage key leaks album id: %q", p.StorageKey)
+	}
+	if p.OriginalURL == "" {
+		t.Fatalf("original url not set")
+	}
+	if p.ThumbURL != "" || p.PreviewURL != "" {
+		t.Fatalf("variants should be pending, got thumb=%q preview=%q", p.ThumbURL, p.PreviewURL)
+	}
+
+	orig, err := svc.store.OriginalObject(ctx, p.ID)
+	if err != nil {
+		t.Fatalf("original object: %v", err)
+	}
+	if orig.State != ObjectReady {
+		t.Fatalf("original object state = %q, want ready", orig.State)
+	}
+	if n, err := svc.store.ObjectRefCount(ctx, orig.ID); err != nil || n != 1 {
+		t.Fatalf("original ref count = %d err=%v, want 1", n, err)
+	}
+
+	var jobs int
+	if err := pool.QueryRow(ctx, `SELECT count(*) FROM variant_jobs WHERE photo_id = $1`, p.ID).Scan(&jobs); err != nil {
+		t.Fatalf("count jobs: %v", err)
+	}
+	if jobs != 1 {
+		t.Fatalf("variant jobs = %d, want 1", jobs)
+	}
+
+	list, _, err := svc.List(ctx, album, user, "", nil, 50)
+	if err != nil || len(list) != 1 {
+		t.Fatalf("list: %v len=%d", err, len(list))
+	}
+	if list[0].MimeType != "image/png" || list[0].Width != 4 || list[0].Height != 4 {
+		t.Fatalf("derived fields wrong: mime=%q %dx%d", list[0].MimeType, list[0].Width, list[0].Height)
+	}
+	if list[0].OriginalURL == "" {
+		t.Fatalf("list original url not set")
+	}
+}

backend/internal/photos/worker.go

@@ -0,0 +1,210 @@
+package photos
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"log/slog"
+	"time"
+
+	"shared-album/internal/auth"
+)
+
+const maxVariantAttempts = 5
+
+// Worker is the background reconciler. It drives the variant generation queue
+// and the object garbage collector entirely from the state recorded in the
+// metadata layer, so it resumes correctly after a restart.
+type Worker struct {
+	svc        *Service
+	interval   time.Duration
+	batch      int
+	pendingTTL time.Duration
+	lease      time.Duration
+}
+
+// NewWorker builds a worker. Parameters are clamped to sane defaults.
+func NewWorker(svc *Service, interval time.Duration, batch int, pendingTTL time.Duration) *Worker {
+	if interval <= 0 {
+		interval = 5 * time.Second
+	}
+	if batch <= 0 {
+		batch = 10
+	}
+	if pendingTTL <= 0 {
+		pendingTTL = 10 * time.Minute
+	}
+	return &Worker{
+		svc:        svc,
+		interval:   interval,
+		batch:      batch,
+		pendingTTL: pendingTTL,
+		lease:      interval * 4,
+	}
+}
+
+// Run loops until the context is cancelled.
+func (w *Worker) Run(ctx context.Context) {
+	slog.Info("background worker started", "interval", w.interval)
+	defer slog.Info("background worker stopped")
+	ticker := time.NewTicker(w.interval)
+	defer ticker.Stop()
+	for {
+		w.tick(ctx)
+		select {
+		case <-ctx.Done():
+			return
+		case <-ticker.C:
+		}
+	}
+}
+
+func (w *Worker) tick(ctx context.Context) {
+	w.processVariantJobs(ctx)
+	w.collectGarbage(ctx)
+	w.reapStalePending(ctx)
+}
+
+func (w *Worker) processVariantJobs(ctx context.Context) {
+	ids, err := w.svc.store.ClaimVariantJobs(ctx, w.batch, w.lease)
+	if err != nil {
+		slog.Error("claim variant jobs", "error", err)
+		return
+	}
+	for _, id := range ids {
+		w.generateVariants(ctx, id)
+	}
+}
+
+func (w *Worker) generateVariants(ctx context.Context, photoID string) {
+	orig, err := w.svc.store.OriginalObject(ctx, photoID)
+	if err != nil {
+		// The photo or its original binding is gone; nothing to do.
+		_ = w.svc.store.CompleteVariantJob(ctx, photoID)
+		return
+	}
+	if orig.State != ObjectReady {
+		w.fail(ctx, photoID, "original object is not ready")
+		return
+	}
+	data, err := w.svc.storage.Get(ctx, orig.StorageKey)
+	if err != nil {
+		w.fail(ctx, photoID, "fetch original: "+err.Error())
+		return
+	}
+	thumb, preview, err := buildVariants(data)
+	if err != nil {
+		w.fail(ctx, photoID, "build variants: "+err.Error())
+		return
+	}
+	siblings, err := w.svc.store.PhotosByOriginalObject(ctx, orig.ID)
+	if err != nil || len(siblings) == 0 {
+		siblings = []string{photoID}
+	}
+	if err := w.createVariant(ctx, siblings, RoleThumb, thumb); err != nil {
+		w.fail(ctx, photoID, "store thumb: "+err.Error())
+		return
+	}
+	if err := w.createVariant(ctx, siblings, RolePreview, preview); err != nil {
+		w.fail(ctx, photoID, "store preview: "+err.Error())
+		return
+	}
+	_ = w.svc.store.CompleteVariantJob(ctx, photoID)
+	for _, pid := range siblings {
+		w.notify(ctx, pid)
+	}
+}
+
+// createVariant stores one derived object and binds it to every photo sharing
+// the original, so copies reuse the same physical variant.
+func (w *Worker) createVariant(ctx context.Context, photoIDs []string, role string, data []byte) error {
+	objID := auth.NewID()
+	key := objectKey(objID, role, ".webp")
+	obj := &Object{
+		ID:         objID,
+		StorageKey: key,
+		MimeType:   "image/webp",
+		Size:       int64(len(data)),
+		Checksum:   checksum(data),
+	}
+	if err := w.svc.store.CreateObject(ctx, obj); err != nil {
+		return err
+	}
+	if err := w.svc.storage.Put(ctx, key, bytes.NewReader(data), int64(len(data)), "image/webp"); err != nil {
+		_ = w.svc.store.DeleteObjectRow(ctx, objID)
+		return err
+	}
+	if err := w.svc.store.ActivateObject(ctx, objID); err != nil {
+		return err
+	}
+	bound := false
+	for _, pid := range photoIDs {
+		if err := w.svc.store.BindObject(ctx, pid, objID, role); err != nil {
+			if errors.Is(err, ErrObjectNotReady) || errors.Is(err, ErrObjectNotFound) {
+				continue
+			}
+			return err
+		}
+		bound = true
+	}
+	if !bound {
+		// No photo could take the variant; let the collector reclaim it.
+		_ = w.svc.store.MarkObjectDeleting(ctx, objID)
+	}
+	return nil
+}
+
+func (w *Worker) notify(ctx context.Context, photoID string) {
+	p, err := w.svc.store.GetByID(ctx, photoID, "")
+	if err != nil {
+		return
+	}
+	if err := w.svc.attachURLs(ctx, p); err != nil {
+		return
+	}
+	w.svc.hub.Publish(p.AlbumID, "photo.created", p)
+}
+
+func (w *Worker) fail(ctx context.Context, photoID, msg string) {
+	slog.Warn("variant job failed", "photo", photoID, "error", msg)
+	_ = w.svc.store.FailVariantJob(ctx, photoID, msg, maxVariantAttempts)
+}
+
+func (w *Worker) collectGarbage(ctx context.Context) {
+	objs, err := w.svc.store.ClaimGarbage(ctx, w.batch)
+	if err != nil {
+		slog.Error("claim garbage", "error", err)
+		return
+	}
+	for _, o := range objs {
+		w.deleteObject(ctx, o)
+	}
+}
+
+func (w *Worker) reapStalePending(ctx context.Context) {
+	objs, err := w.svc.store.ClaimStalePending(ctx, w.pendingTTL, w.batch)
+	if err != nil {
+		slog.Error("claim stale pending", "error", err)
+		return
+	}
+	for _, o := range objs {
+		w.deleteObject(ctx, o)
+	}
+}
+
+// deleteObject removes an object's blob then its row. If a binding appeared
+// meanwhile the object is returned to ready; if the storage delete fails the
+// row stays deleting and is retried on the next pass.
+func (w *Worker) deleteObject(ctx context.Context, o Object) {
+	if n, err := w.svc.store.ObjectRefCount(ctx, o.ID); err == nil && n > 0 {
+		_ = w.svc.store.SetObjectState(ctx, o.ID, ObjectReady)
+		return
+	}
+	if err := w.svc.storage.Delete(ctx, o.StorageKey); err != nil {
+		slog.Warn("delete object blob", "object", o.ID, "error", err)
+		return
+	}
+	if err := w.svc.store.DeleteObjectRow(ctx, o.ID); err != nil && !errors.Is(err, ErrObjectNotFound) {
+		slog.Warn("delete object row", "object", o.ID, "error", err)
+	}
+}

backend/internal/photos/worker_test.go

@@ -0,0 +1,92 @@
+package photos
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+
+	"shared-album/internal/storage"
+)
+
+func TestWorkerGeneratesVariantsAndCollects(t *testing.T) {
+	pool := testPool(t)
+	svc, cl := newTestService(t, pool)
+	runWorkerFlow(t, pool, svc, cl)
+}
+
+func TestWorkerGeneratesVariantsWithFS(t *testing.T) {
+	pool := testPool(t)
+	svc, cl := newTestServiceFS(t, pool)
+	runWorkerFlow(t, pool, svc, cl)
+}
+
+func runWorkerFlow(t *testing.T, pool *pgxpool.Pool, svc *Service, cl storage.Backend) {
+	t.Helper()
+	ctx := context.Background()
+	user := createUser(t, ctx, pool)
+	album := createAlbum(t, ctx, pool, user)
+
+	p, err := svc.Upload(ctx, UploadInput{
+		AlbumID:  album,
+		UserID:   user,
+		Filename: "photo.png",
+		MimeType: "image/png",
+		Data:     makePNG(t),
+	})
+	if err != nil {
+		t.Fatalf("upload: %v", err)
+	}
+	t.Cleanup(func() { cleanupPhoto(t, ctx, pool, cl, p.ID) })
+
+	w := NewWorker(svc, time.Second, 10, time.Minute)
+	w.processVariantJobs(ctx)
+
+	refreshed, err := svc.store.GetByID(ctx, p.ID, "")
+	if err != nil {
+		t.Fatalf("get refreshed: %v", err)
+	}
+	if refreshed.ThumbKey == "" || refreshed.PreviewKey == "" {
+		t.Fatalf("variants not bound: thumb=%q preview=%q", refreshed.ThumbKey, refreshed.PreviewKey)
+	}
+	if err := svc.attachURLs(ctx, refreshed); err != nil {
+		t.Fatalf("attach urls: %v", err)
+	}
+	if refreshed.ThumbURL == "" || refreshed.PreviewURL == "" {
+		t.Fatalf("variant urls not set")
+	}
+
+	var jobs int
+	if err := pool.QueryRow(ctx, `SELECT count(*) FROM variant_jobs WHERE photo_id = $1`, p.ID).Scan(&jobs); err != nil {
+		t.Fatalf("count jobs: %v", err)
+	}
+	if jobs != 0 {
+		t.Fatalf("variant job not completed: %d left", jobs)
+	}
+
+	objectIDs, err := svc.store.PhotoObjectIDs(ctx, p.ID)
+	if err != nil || len(objectIDs) != 3 {
+		t.Fatalf("expected 3 bound objects, got %v err=%v", objectIDs, err)
+	}
+
+	if err := svc.PermanentDelete(ctx, p.ID, user); err != nil {
+		t.Fatalf("permanent delete: %v", err)
+	}
+	// Run the collector until the objects are gone (bounded to avoid hangs).
+	for attempt := 0; attempt < 100 && countObjects(t, ctx, pool, objectIDs) > 0; attempt++ {
+		w.collectGarbage(ctx)
+	}
+	if n := countObjects(t, ctx, pool, objectIDs); n != 0 {
+		t.Fatalf("%d objects were not collected", n)
+	}
+}
+
+func countObjects(t *testing.T, ctx context.Context, pool *pgxpool.Pool, ids []string) int {
+	t.Helper()
+	var n int
+	if err := pool.QueryRow(ctx, `SELECT count(*) FROM objects WHERE id = ANY($1)`, ids).Scan(&n); err != nil {
+		t.Fatalf("count objects: %v", err)
+	}
+	return n
+}

backend/internal/reconcile/reconcile.go

@@ -0,0 +1,74 @@
+// Package reconcile computes the difference between the object storage and the
+// metadata journal so orphaned blobs can be reported and, on request, removed.
+package reconcile
+
+import (
+	"sort"
+	"strings"
+	"time"
+
+	"shared-album/internal/storage"
+)
+
+// Result holds the two kinds of divergence between storage and the journal.
+type Result struct {
+	// Orphans are keys present in storage but absent from the journal; they are
+	// candidates for deletion.
+	Orphans []string
+	// Missing are keys present in the journal but absent from storage; they are
+	// reported only and never modified.
+	Missing []string
+}
+
+// Classify compares the listed storage objects with the journaled keys.
+func Classify(objects []storage.ObjectInfo, journaled []string) Result {
+	have := make(map[string]struct{}, len(journaled))
+	for _, k := range journaled {
+		have[k] = struct{}{}
+	}
+	seen := make(map[string]struct{}, len(objects))
+	var orphans []string
+	for _, o := range objects {
+		if _, dup := seen[o.Key]; dup {
+			continue
+		}
+		seen[o.Key] = struct{}{}
+		if _, ok := have[o.Key]; !ok {
+			orphans = append(orphans, o.Key)
+		}
+	}
+	var missing []string
+	for _, k := range journaled {
+		if _, ok := seen[k]; !ok {
+			missing = append(missing, k)
+		}
+	}
+	sort.Strings(orphans)
+	sort.Strings(missing)
+	return Result{Orphans: orphans, Missing: missing}
+}
+
+// Deletable selects orphaned keys that are safe to remove: within prefix and
+// older than minAge (a guard against racing an in-flight upload whose row is
+// not written yet).
+func Deletable(objects []storage.ObjectInfo, res Result, prefix string, minAge time.Duration, now time.Time) []string {
+	orphans := make(map[string]struct{}, len(res.Orphans))
+	for _, k := range res.Orphans {
+		orphans[k] = struct{}{}
+	}
+	var out []string
+	for _, o := range objects {
+		if _, ok := orphans[o.Key]; !ok {
+			continue
+		}
+		if prefix != "" && !strings.HasPrefix(o.Key, prefix) {
+			continue
+		}
+		if now.Sub(o.ModTime) < minAge {
+			continue
+		}
+		out = append(out, o.Key)
+	}
+	sort.Strings(out)
+	return out
+}

backend/internal/reconcile/reconcile_test.go

@@ -0,0 +1,41 @@
+package reconcile
+
+import (
+	"reflect"
+	"testing"
+	"time"
+
+	"shared-album/internal/storage"
+)
+
+func TestClassify(t *testing.T) {
+	now := time.Now()
+	objects := []storage.ObjectInfo{
+		{Key: "objects/a/original.jpg", ModTime: now},
+		{Key: "objects/b/original.jpg", ModTime: now},
+	}
+	journaled := []string{"objects/b/original.jpg", "objects/c/original.jpg"}
+
+	got := Classify(objects, journaled)
+	if !reflect.DeepEqual(got.Orphans, []string{"objects/a/original.jpg"}) {
+		t.Fatalf("orphans = %v", got.Orphans)
+	}
+	if !reflect.DeepEqual(got.Missing, []string{"objects/c/original.jpg"}) {
+		t.Fatalf("missing = %v", got.Missing)
+	}
+}
+
+func TestDeletableRespectsAgeAndPrefix(t *testing.T) {
+	now := time.Now()
+	objects := []storage.ObjectInfo{
+		{Key: "objects/old/original.jpg", ModTime: now.Add(-2 * time.Hour)},
+		{Key: "objects/new/original.jpg", ModTime: now.Add(-1 * time.Minute)},
+		{Key: "misc/other.bin", ModTime: now.Add(-2 * time.Hour)},
+	}
+	res := Result{Orphans: []string{"objects/old/original.jpg", "objects/new/original.jpg", "misc/other.bin"}}
+
+	got := Deletable(objects, res, "objects/", time.Hour, now)
+	if !reflect.DeepEqual(got, []string{"objects/old/original.jpg"}) {
+		t.Fatalf("deletable = %v, want only the old in-prefix orphan", got)
+	}
+}

backend/internal/repo/contract/contract.go

@@ -0,0 +1,560 @@
+// Package contract holds a backend-agnostic test suite for the metadata
+// repositories. The same suite runs against PostgreSQL and SQLite so both
+// implementations are held to identical observable behaviour.
+package contract
+
+import (
+	"context"
+	"errors"
+	"testing"
+	"time"
+
+	"shared-album/internal/albums"
+	"shared-album/internal/auth"
+	"shared-album/internal/members"
+	"shared-album/internal/models"
+	"shared-album/internal/notifications"
+	"shared-album/internal/photos"
+	"shared-album/internal/settings"
+	"shared-album/internal/sharelinks"
+	"shared-album/internal/social"
+)
+
+// Repos bundles one repository per domain plus a Reset hook that clears all
+// metadata so each subtest starts from an empty state.
+type Repos struct {
+	Auth          auth.Repository
+	Albums        albums.Repository
+	Members       members.Repository
+	Photos        photos.Repository
+	Social        social.Repository
+	Notifications notifications.Repository
+	ShareLinks    sharelinks.Repository
+	Settings      settings.Repository
+	Reset         func(ctx context.Context) error
+}
+
+// Run executes the whole contract suite against the given repositories.
+func Run(t *testing.T, r Repos) {
+	t.Helper()
+	cases := []struct {
+		name string
+		fn   func(*testing.T, context.Context, Repos)
+	}{
+		{"Auth", testAuth},
+		{"Albums", testAlbums},
+		{"Members", testMembers},
+		{"Notifications", testNotifications},
+		{"ShareLinks", testShareLinks},
+		{"Social", testSocial},
+		{"Photos", testPhotos},
+		{"Objects", testObjects},
+		{"Settings", testSettings},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			if err := r.Reset(context.Background()); err != nil {
+				t.Fatalf("reset: %v", err)
+			}
+			tc.fn(t, context.Background(), r)
+		})
+	}
+}
+
+func newID() string { return auth.NewID() }
+
+func seedUser(t *testing.T, ctx context.Context, r Repos, name string) *models.User {
+	t.Helper()
+	u := &models.User{ID: newID(), Email: newID()[:10] + "@test.local", PasswordHash: "x", Name: name}
+	if err := r.Auth.CreateUser(ctx, u); err != nil {
+		t.Fatalf("create user: %v", err)
+	}
+	return u
+}
+
+func seedAlbum(t *testing.T, ctx context.Context, r Repos, ownerID string) *models.Album {
+	t.Helper()
+	a := &models.Album{ID: newID(), OwnerID: ownerID, Title: "Album"}
+	if err := r.Albums.Create(ctx, a); err != nil {
+		t.Fatalf("create album: %v", err)
+	}
+	return a
+}
+
+func seedPhoto(t *testing.T, ctx context.Context, r Repos, uploaderID, albumID string) *models.Photo {
+	t.Helper()
+	obj := &photos.Object{ID: newID(), StorageKey: "objects/" + newID(), State: photos.ObjectPending}
+	p := &models.Photo{ID: newID(), AlbumID: albumID, UploaderID: uploaderID, OriginalFilename: "p.jpg"}
+	if err := r.Photos.CreateWithOriginal(ctx, p, obj); err != nil {
+		t.Fatalf("create photo: %v", err)
+	}
+	if err := r.Photos.ActivateObject(ctx, obj.ID); err != nil {
+		t.Fatalf("activate object: %v", err)
+	}
+	return p
+}
+
+func testAuth(t *testing.T, ctx context.Context, r Repos) {
+	u := seedUser(t, ctx, r, "Tester")
+
+	byEmail, err := r.Auth.GetUserByEmail(ctx, u.Email)
+	if err != nil || byEmail.ID != u.ID {
+		t.Fatalf("get by email: %v id=%v", err, byEmail)
+	}
+	if _, err := r.Auth.GetUserByID(ctx, u.ID); err != nil {
+		t.Fatalf("get by id: %v", err)
+	}
+	if _, err := r.Auth.GetUserByEmail(ctx, "missing@test.local"); !errors.Is(err, auth.ErrNotFound) {
+		t.Fatalf("missing email err = %v, want ErrNotFound", err)
+	}
+
+	if err := r.Auth.UpdatePreferences(ctx, u.ID, []byte(`{"theme":"dark"}`)); err != nil {
+		t.Fatalf("update preferences: %v", err)
+	}
+	got, _ := r.Auth.GetUserByID(ctx, u.ID)
+	if got.Preferences["theme"] != "dark" {
+		t.Fatalf("preferences not applied: %+v", got.Preferences)
+	}
+	if err := r.Auth.UpdatePreferences(ctx, "missing", []byte(`{}`)); !errors.Is(err, auth.ErrNotFound) {
+		t.Fatalf("update missing prefs err = %v, want ErrNotFound", err)
+	}
+
+	hash := newID()
+	rt := &models.RefreshToken{ID: newID(), UserID: u.ID, TokenHash: hash, ExpiresAt: time.Now().Add(time.Hour)}
+	if err := r.Auth.CreateRefreshToken(ctx, rt); err != nil {
+		t.Fatalf("create refresh: %v", err)
+	}
+	fetched, err := r.Auth.GetRefreshToken(ctx, hash)
+	if err != nil || fetched.ID != rt.ID {
+		t.Fatalf("get refresh: %v id=%v", err, fetched)
+	}
+	if err := r.Auth.RevokeRefreshToken(ctx, rt.ID); err != nil {
+		t.Fatalf("revoke refresh: %v", err)
+	}
+	fetched, _ = r.Auth.GetRefreshToken(ctx, hash)
+	if fetched.RevokedAt == nil {
+		t.Fatalf("refresh not revoked")
+	}
+	if err := r.Auth.RevokeAllUserTokens(ctx, u.ID); err != nil {
+		t.Fatalf("revoke all: %v", err)
+	}
+}
+
+func testAlbums(t *testing.T, ctx context.Context, r Repos) {
+	owner := seedUser(t, ctx, r, "Owner")
+	a := seedAlbum(t, ctx, r, owner.ID)
+	if a.CreatedAt.IsZero() || a.UpdatedAt.IsZero() {
+		t.Fatalf("album timestamps not returned: %+v", a)
+	}
+
+	got, err := r.Albums.GetByID(ctx, a.ID)
+	if err != nil || got.Title != "Album" {
+		t.Fatalf("get: %v %+v", err, got)
+	}
+	if oid, err := r.Albums.OwnerID(ctx, a.ID); err != nil || oid != owner.ID {
+		t.Fatalf("owner id: %v %v", oid, err)
+	}
+	list, err := r.Albums.ListForUser(ctx, owner.ID)
+	if err != nil || len(list) != 1 {
+		t.Fatalf("list: %v len=%d", err, len(list))
+	}
+
+	a.Title = "Renamed"
+	if err := r.Albums.Update(ctx, a); err != nil {
+		t.Fatalf("update: %v", err)
+	}
+	got, _ = r.Albums.GetByID(ctx, a.ID)
+	if got.Title != "Renamed" {
+		t.Fatalf("update not applied: %q", got.Title)
+	}
+
+	if err := r.Albums.Delete(ctx, a.ID); err != nil {
+		t.Fatalf("delete: %v", err)
+	}
+	if _, err := r.Albums.GetByID(ctx, a.ID); !errors.Is(err, albums.ErrNotFound) {
+		t.Fatalf("after delete err = %v, want ErrNotFound", err)
+	}
+}
+
+func testMembers(t *testing.T, ctx context.Context, r Repos) {
+	owner := seedUser(t, ctx, r, "Owner")
+	member := seedUser(t, ctx, r, "Member")
+	a := seedAlbum(t, ctx, r, owner.ID)
+
+	if role, _ := r.Members.Role(ctx, a.ID, member.ID); role != "" {
+		t.Fatalf("role before add = %q", role)
+	}
+	if err := r.Members.Add(ctx, a.ID, member.ID, "member", &owner.ID); err != nil {
+		t.Fatalf("add: %v", err)
+	}
+	if role, err := r.Members.Role(ctx, a.ID, member.ID); err != nil || role != "member" {
+		t.Fatalf("role = %q err=%v", role, err)
+	}
+	list, err := r.Members.List(ctx, a.ID)
+	if err != nil || len(list) != 1 || list[0].User.Name != "Member" {
+		t.Fatalf("list: %v %+v", err, list)
+	}
+	if err := r.Members.UpdateRole(ctx, a.ID, member.ID, "editor"); err != nil {
+		t.Fatalf("update role: %v", err)
+	}
+	if role, _ := r.Members.Role(ctx, a.ID, member.ID); role != "editor" {
+		t.Fatalf("role not updated: %q", role)
+	}
+
+	inv := &models.Invite{ID: newID(), AlbumID: a.ID, Token: newID(), Role: "viewer", CreatedBy: owner.ID, ExpiresAt: time.Now().Add(time.Hour), MaxUses: 2}
+	if err := r.Members.CreateInvite(ctx, inv); err != nil {
+		t.Fatalf("create invite: %v", err)
+	}
+	if inv.CreatedAt.IsZero() {
+		t.Fatalf("invite created_at not returned")
+	}
+	got, err := r.Members.GetInviteByToken(ctx, inv.Token)
+	if err != nil || got.Role != "viewer" || got.MaxUses != 2 {
+		t.Fatalf("get invite: %v %+v", err, got)
+	}
+	if err := r.Members.IncrementUses(ctx, inv.ID); err != nil {
+		t.Fatalf("increment: %v", err)
+	}
+	got, _ = r.Members.GetInviteByToken(ctx, inv.Token)
+	if got.Uses != 1 {
+		t.Fatalf("uses = %d, want 1", got.Uses)
+	}
+	if _, err := r.Members.GetInviteByToken(ctx, "missing"); !errors.Is(err, members.ErrNotFound) {
+		t.Fatalf("missing invite err = %v, want ErrNotFound", err)
+	}
+
+	if err := r.Members.Remove(ctx, a.ID, member.ID); err != nil {
+		t.Fatalf("remove: %v", err)
+	}
+	if role, _ := r.Members.Role(ctx, a.ID, member.ID); role != "" {
+		t.Fatalf("member not removed: %q", role)
+	}
+	if err := r.Members.Remove(ctx, a.ID, member.ID); !errors.Is(err, members.ErrNotFound) {
+		t.Fatalf("remove missing err = %v, want ErrNotFound", err)
+	}
+}
+
+func testNotifications(t *testing.T, ctx context.Context, r Repos) {
+	u := seedUser(t, ctx, r, "Notify")
+	n := &models.Notification{ID: newID(), UserID: u.ID, Type: "test", PayloadJSON: map[string]any{"k": "v"}}
+	if err := r.Notifications.Create(ctx, n); err != nil {
+		t.Fatalf("create: %v", err)
+	}
+	if n.CreatedAt.IsZero() {
+		t.Fatalf("notification created_at not returned")
+	}
+	list, err := r.Notifications.List(ctx, u.ID, 10)
+	if err != nil || len(list) != 1 || list[0].PayloadJSON["k"] != "v" {
+		t.Fatalf("list: %v %+v", err, list)
+	}
+	if err := r.Notifications.MarkRead(ctx, n.ID, u.ID); err != nil {
+		t.Fatalf("mark read: %v", err)
+	}
+	list, _ = r.Notifications.List(ctx, u.ID, 10)
+	if list[0].ReadAt == nil {
+		t.Fatalf("notification not marked read")
+	}
+	if err := r.Notifications.MarkRead(ctx, newID(), u.ID); !errors.Is(err, notifications.ErrNotFound) {
+		t.Fatalf("mark missing err = %v, want ErrNotFound", err)
+	}
+}
+
+func testShareLinks(t *testing.T, ctx context.Context, r Repos) {
+	owner := seedUser(t, ctx, r, "Owner")
+	a := seedAlbum(t, ctx, r, owner.ID)
+
+	l := &models.ShareLink{ID: newID(), AlbumID: a.ID, Token: newID(), CreatedBy: owner.ID, ExpiresAt: time.Now().Add(time.Hour)}
+	if err := r.ShareLinks.Create(ctx, l); err != nil {
+		t.Fatalf("create: %v", err)
+	}
+	if l.CreatedAt.IsZero() {
+		t.Fatalf("share link created_at not returned")
+	}
+	got, err := r.ShareLinks.GetByToken(ctx, l.Token)
+	if err != nil || !got.Active(time.Now()) {
+		t.Fatalf("get token: %v %+v", err, got)
+	}
+	list, err := r.ShareLinks.ListByAlbum(ctx, a.ID)
+	if err != nil || len(list) != 1 {
+		t.Fatalf("list: %v len=%d", err, len(list))
+	}
+	if err := r.ShareLinks.Revoke(ctx, l.ID, a.ID); err != nil {
+		t.Fatalf("revoke: %v", err)
+	}
+	got, _ = r.ShareLinks.GetByToken(ctx, l.Token)
+	if got.Active(time.Now()) {
+		t.Fatalf("link still active after revoke")
+	}
+	if err := r.ShareLinks.Revoke(ctx, l.ID, a.ID); !errors.Is(err, sharelinks.ErrNotFound) {
+		t.Fatalf("revoke again err = %v, want ErrNotFound", err)
+	}
+	if _, err := r.ShareLinks.GetByToken(ctx, "missing"); !errors.Is(err, sharelinks.ErrNotFound) {
+		t.Fatalf("missing token err = %v, want ErrNotFound", err)
+	}
+}
+
+func testSocial(t *testing.T, ctx context.Context, r Repos) {
+	owner := seedUser(t, ctx, r, "Owner")
+	a := seedAlbum(t, ctx, r, owner.ID)
+	p := seedPhoto(t, ctx, r, owner.ID, a.ID)
+
+	if err := r.Social.Like(ctx, p.ID, owner.ID); err != nil {
+		t.Fatalf("like: %v", err)
+	}
+	if err := r.Social.Like(ctx, p.ID, owner.ID); err != nil {
+		t.Fatalf("like twice: %v", err)
+	}
+	if err := r.Social.Unlike(ctx, p.ID, owner.ID); err != nil {
+		t.Fatalf("unlike: %v", err)
+	}
+
+	c := &models.Comment{ID: newID(), PhotoID: p.ID, UserID: owner.ID, Text: "hi"}
+	if err := r.Social.CreateComment(ctx, c); err != nil {
+		t.Fatalf("create comment: %v", err)
+	}
+	if c.CreatedAt.IsZero() || c.UpdatedAt.IsZero() {
+		t.Fatalf("comment timestamps not returned: %+v", c)
+	}
+	list, err := r.Social.ListComments(ctx, p.ID)
+	if err != nil || len(list) != 1 || list[0].Text != "hi" {
+		t.Fatalf("list comments: %v %+v", err, list)
+	}
+	got, err := r.Social.GetComment(ctx, c.ID)
+	if err != nil || got.Text != "hi" {
+		t.Fatalf("get comment: %v %+v", err, got)
+	}
+	if err := r.Social.DeleteComment(ctx, c.ID); err != nil {
+		t.Fatalf("delete comment: %v", err)
+	}
+	if _, err := r.Social.GetComment(ctx, c.ID); !errors.Is(err, social.ErrNotFound) {
+		t.Fatalf("get deleted err = %v, want ErrNotFound", err)
+	}
+	if err := r.Social.DeleteComment(ctx, c.ID); !errors.Is(err, social.ErrNotFound) {
+		t.Fatalf("delete again err = %v, want ErrNotFound", err)
+	}
+}
+
+func testPhotos(t *testing.T, ctx context.Context, r Repos) {
+	owner := seedUser(t, ctx, r, "Owner")
+	a := seedAlbum(t, ctx, r, owner.ID)
+	p := seedPhoto(t, ctx, r, owner.ID, a.ID)
+	if p.CreatedAt.IsZero() {
+		t.Fatalf("photo created_at not returned")
+	}
+	got, err := r.Photos.GetByID(ctx, p.ID, "")
+	if err != nil || got.StorageKey == "" {
+		t.Fatalf("get photo: %v %+v", err, got)
+	}
+	list, err := r.Photos.List(ctx, photos.ListParams{AlbumID: a.ID, Limit: 10})
+	if err != nil || len(list) != 1 {
+		t.Fatalf("list: %v len=%d", err, len(list))
+	}
+
+	tag, err := r.Photos.EnsureTag(ctx, owner.ID, "Vacation")
+	if err != nil || tag.Name != "Vacation" {
+		t.Fatalf("ensure tag: %v %+v", err, tag)
+	}
+	tag2, err := r.Photos.EnsureTag(ctx, owner.ID, "vacation")
+	if err != nil || tag2.ID != tag.ID {
+		t.Fatalf("ensure tag case-insensitive: %v %+v", err, tag2)
+	}
+	if err := r.Photos.AttachTag(ctx, p.ID, tag.ID); err != nil {
+		t.Fatalf("attach tag: %v", err)
+	}
+	got, _ = r.Photos.GetByID(ctx, p.ID, owner.ID)
+	if len(got.Tags) != 1 || got.Tags[0].Name != "Vacation" {
+		t.Fatalf("photo tags = %+v", got.Tags)
+	}
+	if owned, _ := r.Photos.TagOwnedBy(ctx, tag.ID, owner.ID); !owned {
+		t.Fatalf("tag not owned")
+	}
+	tags, err := r.Photos.ListTags(ctx, owner.ID, "vac")
+	if err != nil || len(tags) != 1 {
+		t.Fatalf("list tags: %v len=%d", err, len(tags))
+	}
+	if err := r.Photos.DetachTag(ctx, p.ID, tag.ID); err != nil {
+		t.Fatalf("detach tag: %v", err)
+	}
+
+	r.Photos.SetCoverIfEmpty(ctx, a.ID, p.ID)
+	al, _ := r.Albums.GetByID(ctx, a.ID)
+	if al.CoverPhotoID == nil || *al.CoverPhotoID != p.ID {
+		t.Fatalf("cover not set: %+v", al.CoverPhotoID)
+	}
+
+	if err := r.Photos.SetDeleted(ctx, p.ID, true); err != nil {
+		t.Fatalf("soft delete: %v", err)
+	}
+	if n, _ := r.Photos.TrashCount(ctx, owner.ID); n != 1 {
+		t.Fatalf("trash count = %d, want 1", n)
+	}
+	trash, err := r.Photos.ListTrash(ctx, owner.ID)
+	if err != nil || len(trash) != 1 {
+		t.Fatalf("trash: %v len=%d", err, len(trash))
+	}
+	if err := r.Photos.RestoreToAlbum(ctx, p.ID, a.ID); err != nil {
+		t.Fatalf("restore: %v", err)
+	}
+	if n, _ := r.Photos.TrashCount(ctx, owner.ID); n != 0 {
+		t.Fatalf("trash count after restore = %d", n)
+	}
+
+	if err := r.Photos.UpdateFilename(ctx, p.ID, "renamed.jpg"); err != nil {
+		t.Fatalf("update filename: %v", err)
+	}
+	got, _ = r.Photos.GetByID(ctx, p.ID, "")
+	if got.OriginalFilename != "renamed.jpg" {
+		t.Fatalf("filename = %q", got.OriginalFilename)
+	}
+	if ok, _ := r.Photos.AlbumExists(ctx, a.ID); !ok {
+		t.Fatalf("album should exist")
+	}
+
+	if err := r.Photos.HardDelete(ctx, p.ID); err != nil {
+		t.Fatalf("hard delete: %v", err)
+	}
+	if _, err := r.Photos.GetByID(ctx, p.ID, ""); !errors.Is(err, photos.ErrNotFound) {
+		t.Fatalf("get deleted err = %v, want ErrNotFound", err)
+	}
+}
+
+func testObjects(t *testing.T, ctx context.Context, r Repos) {
+	owner := seedUser(t, ctx, r, "Owner")
+	a := seedAlbum(t, ctx, r, owner.ID)
+	p := seedPhoto(t, ctx, r, owner.ID, a.ID)
+
+	orig, err := r.Photos.OriginalObject(ctx, p.ID)
+	if err != nil || orig.State != photos.ObjectReady {
+		t.Fatalf("original object: %v %+v", err, orig)
+	}
+	keys, err := r.Photos.AllStorageKeys(ctx)
+	if err != nil || !contains(keys, orig.StorageKey) {
+		t.Fatalf("AllStorageKeys = %v err=%v, want %s", keys, err, orig.StorageKey)
+	}
+	if refs, _ := r.Photos.ObjectRefCount(ctx, orig.ID); refs != 1 {
+		t.Fatalf("refs = %d, want 1", refs)
+	}
+	sibs, _ := r.Photos.PhotosByOriginalObject(ctx, orig.ID)
+	if len(sibs) != 1 || sibs[0] != p.ID {
+		t.Fatalf("siblings = %+v", sibs)
+	}
+
+	thumb := &photos.Object{ID: newID(), StorageKey: "objects/" + newID(), MimeType: "image/webp", State: photos.ObjectPending}
+	if err := r.Photos.CreateObject(ctx, thumb); err != nil {
+		t.Fatalf("create object: %v", err)
+	}
+	if err := r.Photos.BindObject(ctx, p.ID, thumb.ID, photos.RoleThumb); !errors.Is(err, photos.ErrObjectNotReady) {
+		t.Fatalf("bind pending err = %v, want ErrObjectNotReady", err)
+	}
+	if err := r.Photos.ActivateObject(ctx, thumb.ID); err != nil {
+		t.Fatalf("activate: %v", err)
+	}
+	if err := r.Photos.BindObject(ctx, p.ID, thumb.ID, photos.RoleThumb); err != nil {
+		t.Fatalf("bind thumb: %v", err)
+	}
+	if refs, _ := r.Photos.ObjectRefCount(ctx, thumb.ID); refs != 1 {
+		t.Fatalf("thumb refs = %d, want 1", refs)
+	}
+
+	// After the photo is gone, its objects have no bindings and are collectible.
+	if err := r.Photos.HardDelete(ctx, p.ID); err != nil {
+		t.Fatalf("hard delete: %v", err)
+	}
+	claimed, err := r.Photos.ClaimGarbage(ctx, 10)
+	if err != nil {
+		t.Fatalf("claim garbage: %v", err)
+	}
+	got := map[string]bool{}
+	for _, o := range claimed {
+		got[o.ID] = true
+	}
+	if !got[orig.ID] || !got[thumb.ID] {
+		t.Fatalf("claimed = %+v, want original and thumb", got)
+	}
+	for _, o := range claimed {
+		if err := r.Photos.DeleteObjectRow(ctx, o.ID); err != nil {
+			t.Fatalf("delete object row: %v", err)
+		}
+	}
+	if again, _ := r.Photos.ClaimGarbage(ctx, 10); len(again) != 0 {
+		t.Fatalf("garbage reclaimed: %+v", again)
+	}
+
+	// Stale pending objects are reaped. A negative age puts the threshold in
+	// the future so the mechanism is exercised without depending on clock skew
+	// between the test process and the database.
+	stale := &photos.Object{ID: newID(), StorageKey: "objects/" + newID(), State: photos.ObjectPending}
+	if err := r.Photos.CreateObject(ctx, stale); err != nil {
+		t.Fatalf("create stale: %v", err)
+	}
+	staleClaimed, err := r.Photos.ClaimStalePending(ctx, -time.Hour, 10)
+	if err != nil || len(staleClaimed) == 0 {
+		t.Fatalf("claim stale: %v %+v", err, staleClaimed)
+	}
+
+	// Variant queue: a fresh photo has one job.
+	p2 := seedPhoto(t, ctx, r, owner.ID, a.ID)
+	jobs, err := r.Photos.ClaimVariantJobs(ctx, 10, time.Minute)
+	if err != nil {
+		t.Fatalf("claim jobs: %v", err)
+	}
+	if !contains(jobs, p2.ID) {
+		t.Fatalf("jobs = %+v, want %s", jobs, p2.ID)
+	}
+	if err := r.Photos.CompleteVariantJob(ctx, p2.ID); err != nil {
+		t.Fatalf("complete job: %v", err)
+	}
+	if jobs, _ = r.Photos.ClaimVariantJobs(ctx, 10, time.Minute); contains(jobs, p2.ID) {
+		t.Fatalf("completed job still claimed: %+v", jobs)
+	}
+
+	// Failure schedules a retry and eventually abandons the job.
+	p3 := seedPhoto(t, ctx, r, owner.ID, a.ID)
+	if err := r.Photos.FailVariantJob(ctx, p3.ID, "boom", 3); err != nil {
+		t.Fatalf("fail job: %v", err)
+	}
+	if jobs, _ = r.Photos.ClaimVariantJobs(ctx, 10, time.Minute); contains(jobs, p3.ID) {
+		t.Fatalf("failed job retried immediately: %+v", jobs)
+	}
+	for i := 0; i < 3; i++ {
+		if err := r.Photos.FailVariantJob(ctx, p3.ID, "boom", 3); err != nil {
+			t.Fatalf("fail job again: %v", err)
+		}
+	}
+	if jobs, _ = r.Photos.ClaimVariantJobs(ctx, 10, time.Minute); contains(jobs, p3.ID) {
+		t.Fatalf("abandoned job still present: %+v", jobs)
+	}
+}
+
+func testSettings(t *testing.T, ctx context.Context, r Repos) {
+	v, err := r.Settings.Ensure(ctx, settings.JWTSecretKey, func() (string, error) { return "generated-1", nil })
+	if err != nil || v != "generated-1" {
+		t.Fatalf("ensure first: %v %q", err, v)
+	}
+	v2, err := r.Settings.Ensure(ctx, settings.JWTSecretKey, func() (string, error) { return "generated-2", nil })
+	if err != nil || v2 != "generated-1" {
+		t.Fatalf("ensure not idempotent: %v %q", err, v2)
+	}
+	got, ok, err := r.Settings.Get(ctx, settings.JWTSecretKey)
+	if err != nil || !ok || got != "generated-1" {
+		t.Fatalf("get: %v ok=%v %q", err, ok, got)
+	}
+	if _, ok, _ := r.Settings.Get(ctx, "missing"); ok {
+		t.Fatalf("missing key reported present")
+	}
+	if err := r.Settings.Set(ctx, settings.JWTSecretKey, "rotated"); err != nil {
+		t.Fatalf("set: %v", err)
+	}
+	if got, _, _ := r.Settings.Get(ctx, settings.JWTSecretKey); got != "rotated" {
+		t.Fatalf("set not applied: %q", got)
+	}
+}
+
+func contains(list []string, v string) bool {
+	for _, x := range list {
+		if x == v {
+			return true
+		}
+	}
+	return false
+}

backend/internal/repo/contract/postgres_test.go

@@ -0,0 +1,80 @@
+package contract
+
+import (
+	"context"
+	"fmt"
+	"io/fs"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+
+	assets "shared-album"
+	"shared-album/internal/albums"
+	"shared-album/internal/auth"
+	"shared-album/internal/db"
+	"shared-album/internal/members"
+	"shared-album/internal/notifications"
+	"shared-album/internal/photos"
+	"shared-album/internal/settings"
+	"shared-album/internal/sharelinks"
+	"shared-album/internal/social"
+)
+
+// TestPostgresContract runs the shared suite against PostgreSQL inside its own
+// schema, so it never clashes with other packages that use the same database.
+func TestPostgresContract(t *testing.T) {
+	base := os.Getenv("TEST_DATABASE_URL")
+	if base == "" {
+		t.Skip("TEST_DATABASE_URL not set")
+	}
+	ctx := context.Background()
+
+	admin, err := pgxpool.New(ctx, base)
+	if err != nil {
+		t.Skipf("cannot connect: %v", err)
+	}
+	if err := admin.Ping(ctx); err != nil {
+		t.Skipf("cannot ping: %v", err)
+	}
+	t.Cleanup(admin.Close)
+
+	schema := fmt.Sprintf("ct_%d", time.Now().UnixNano())
+	if _, err := admin.Exec(ctx, "CREATE SCHEMA "+schema); err != nil {
+		t.Fatalf("create schema: %v", err)
+	}
+	t.Cleanup(func() {
+		_, _ = admin.Exec(context.Background(), "DROP SCHEMA "+schema+" CASCADE")
+	})
+
+	dsn := base + "&options=-c%20search_path%3D" + schema
+	migFS, err := fs.Sub(assets.Migrations, "migrations")
+	if err != nil {
+		t.Fatalf("migrations fs: %v", err)
+	}
+	if err := db.Migrate(dsn, migFS); err != nil {
+		t.Fatalf("migrate: %v", err)
+	}
+
+	pool, err := pgxpool.New(ctx, dsn)
+	if err != nil {
+		t.Fatalf("pool: %v", err)
+	}
+	t.Cleanup(pool.Close)
+
+	Run(t, Repos{
+		Auth:          auth.NewStore(pool),
+		Albums:        albums.NewStore(pool),
+		Members:       members.NewStore(pool),
+		Photos:        photos.NewStore(pool),
+		Social:        social.NewStore(pool),
+		Notifications: notifications.NewStore(pool),
+		ShareLinks:    sharelinks.NewStore(pool),
+		Settings:      settings.NewStore(pool),
+		Reset: func(ctx context.Context) error {
+			_, err := pool.Exec(ctx, `TRUNCATE users, objects, app_settings CASCADE`)
+			return err
+		},
+	})
+}

backend/internal/repo/contract/sqlite_test.go

@@ -0,0 +1,59 @@
+package contract
+
+import (
+	"context"
+	"io/fs"
+	"path/filepath"
+	"testing"
+
+	assets "shared-album"
+	"shared-album/internal/albums"
+	"shared-album/internal/auth"
+	"shared-album/internal/db"
+	"shared-album/internal/members"
+	"shared-album/internal/notifications"
+	"shared-album/internal/photos"
+	"shared-album/internal/settings"
+	"shared-album/internal/sharelinks"
+	"shared-album/internal/social"
+)
+
+func TestSQLiteContract(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "meta.db")
+	migFS, err := fs.Sub(assets.Migrations, "migrations/sqlite")
+	if err != nil {
+		t.Fatalf("migrations fs: %v", err)
+	}
+	if err := db.MigrateSQLite(path, migFS); err != nil {
+		t.Fatalf("migrate: %v", err)
+	}
+	database, err := db.OpenSQLite(path)
+	if err != nil {
+		t.Fatalf("open: %v", err)
+	}
+	t.Cleanup(func() { database.Close() })
+
+	Run(t, Repos{
+		Auth:          auth.NewSQLiteStore(database),
+		Albums:        albums.NewSQLiteStore(database),
+		Members:       members.NewSQLiteStore(database),
+		Photos:        photos.NewSQLiteStore(database),
+		Social:        social.NewSQLiteStore(database),
+		Notifications: notifications.NewSQLiteStore(database),
+		ShareLinks:    sharelinks.NewSQLiteStore(database),
+		Settings:      settings.NewSQLiteStore(database),
+		Reset: func(ctx context.Context) error {
+			tables := []string{
+				"variant_jobs", "photo_objects", "objects", "photo_tags", "tags",
+				"refresh_tokens", "share_links", "notifications", "likes", "comments",
+				"invites", "album_members", "photos", "albums", "users", "app_settings",
+			}
+			for _, tbl := range tables {
+				if _, err := database.ExecContext(ctx, "DELETE FROM "+tbl); err != nil {
+					return err
+				}
+			}
+			return nil
+		},
+	})
+}

backend/internal/repo/repo_test.go

@@ -29,6 +29,7 @@ func testPool(t *testing.T) *pgxpool.Pool {
 	if err := pool.Ping(context.Background()); err != nil {
 		t.Skipf("cannot ping: %v", err)
 	}
+	t.Cleanup(pool.Close)
 	return pool
 }
 
@@ -48,7 +49,6 @@ func newUser(t *testing.T, ctx context.Context, pool *pgxpool.Pool, name string)
 
 func TestUserRepository(t *testing.T) {
 	pool := testPool(t)
-	defer pool.Close()
 	ctx := context.Background()
 	store := auth.NewStore(pool)
 
@@ -82,7 +82,6 @@ func TestUserRepository(t *testing.T) {
 
 func TestAlbumRepository(t *testing.T) {
 	pool := testPool(t)
-	defer pool.Close()
 	ctx := context.Background()
 	store := albums.NewStore(pool)
 
@@ -126,7 +125,6 @@ func TestAlbumRepository(t *testing.T) {
 
 func TestAlbumCoverRepository(t *testing.T) {
 	pool := testPool(t)
-	defer pool.Close()
 	ctx := context.Background()
 	store := albums.NewStore(pool)
 
@@ -138,18 +136,33 @@ func TestAlbumCoverRepository(t *testing.T) {
 		t.Fatalf("create album: %v", err)
 	}
 
-	insertPhoto := func(id, thumbKey string) {
+	insertPhoto := func(id string) string {
 		t.Helper()
+		origObj := auth.NewID()
+		thumbObj := auth.NewID()
+		thumbKey := "objects/" + thumbObj + "/thumb.webp"
 		if _, err := pool.Exec(ctx,
-			`INSERT INTO photos (id, album_id, uploader_id, storage_key, thumb_key)
-			 VALUES ($1, $2, $3, $4, $5)`,
-			id, a.ID, owner.ID, "albums/"+a.ID+"/original/"+id+".jpg", thumbKey); err != nil {
+			`INSERT INTO objects (id, storage_key, mime_type, state) VALUES
+			 ($1, $2, 'image/jpeg', 'ready'),
+			 ($3, $4, 'image/webp', 'ready')`,
+			origObj, "objects/"+origObj+"/original.jpg", thumbObj, thumbKey); err != nil {
+			t.Fatalf("insert objects: %v", err)
+		}
+		if _, err := pool.Exec(ctx,
+			`INSERT INTO photos (id, album_id, uploader_id) VALUES ($1, $2, $3)`,
+			id, a.ID, owner.ID); err != nil {
 			t.Fatalf("insert photo: %v", err)
 		}
+		if _, err := pool.Exec(ctx,
+			`INSERT INTO photo_objects (photo_id, object_id, role) VALUES ($1, $2, 'original'), ($1, $3, 'thumb')`,
+			id, origObj, thumbObj); err != nil {
+			t.Fatalf("insert bindings: %v", err)
+		}
+		return thumbKey
 	}
 
 	photo1 := auth.NewID()
-	insertPhoto(photo1, "albums/"+a.ID+"/thumb/"+photo1+".webp")
+	thumb1 := insertPhoto(photo1)
 
 	got, err := store.GetByID(ctx, a.ID)
 	if err != nil || got.CoverThumbKey != "" {
@@ -162,12 +175,12 @@ func TestAlbumCoverRepository(t *testing.T) {
 	if got.CoverPhotoID == nil || *got.CoverPhotoID != photo1 {
 		t.Fatalf("cover not set: %+v", got.CoverPhotoID)
 	}
-	if want := "albums/" + a.ID + "/thumb/" + photo1 + ".webp"; got.CoverThumbKey != want {
-		t.Fatalf("cover thumb key = %q want %q", got.CoverThumbKey, want)
+	if got.CoverThumbKey != thumb1 {
+		t.Fatalf("cover thumb key = %q want %q", got.CoverThumbKey, thumb1)
 	}
 
 	photo2 := auth.NewID()
-	insertPhoto(photo2, "thumb-2")
+	thumb2 := insertPhoto(photo2)
 	ps.SetCoverIfEmpty(ctx, a.ID, photo2)
 	got, _ = store.GetByID(ctx, a.ID)
 	if got.CoverPhotoID == nil || *got.CoverPhotoID != photo1 {
@@ -184,14 +197,13 @@ func TestAlbumCoverRepository(t *testing.T) {
 
 	ps.SetCoverIfEmpty(ctx, a.ID, photo2)
 	list, err := store.ListForUser(ctx, owner.ID)
-	if err != nil || len(list) != 1 || list[0].CoverThumbKey != "thumb-2" {
+	if err != nil || len(list) != 1 || list[0].CoverThumbKey != thumb2 {
 		t.Fatalf("list cover key: %v %+v", err, list)
 	}
 }
 
 func TestMemberRepository(t *testing.T) {
 	pool := testPool(t)
-	defer pool.Close()
 	ctx := context.Background()
 
 	owner := newUser(t, ctx, pool, "Owner")
@@ -255,7 +267,6 @@ func TestMemberRepository(t *testing.T) {
 
 func TestShareLinkRepository(t *testing.T) {
 	pool := testPool(t)
-	defer pool.Close()
 	ctx := context.Background()
 
 	owner := newUser(t, ctx, pool, "Owner")

backend/internal/settings/generate.go

@@ -0,0 +1,15 @@
+package settings
+
+import (
+	"crypto/rand"
+	"encoding/base64"
+)
+
+// GenerateSecret returns a new random secret suitable for HMAC signing.
+func GenerateSecret() (string, error) {
+	buf := make([]byte, 32)
+	if _, err := rand.Read(buf); err != nil {
+		return "", err
+	}
+	return base64.RawURLEncoding.EncodeToString(buf), nil
+}

backend/internal/settings/settings.go

@@ -0,0 +1,20 @@
+// Package settings persists application-level key/value settings in the
+// metadata layer. The main use is the token signing secret, generated on first
+// use and reused afterwards.
+package settings
+
+import "context"
+
+// JWTSecretKey is the settings key holding the token signing secret.
+const JWTSecretKey = "jwt_secret"
+
+// Repository reads and writes application settings.
+type Repository interface {
+	// Get returns the value for key and whether it exists.
+	Get(ctx context.Context, key string) (string, bool, error)
+	// Set stores or replaces the value for key.
+	Set(ctx context.Context, key, value string) error
+	// Ensure returns the existing value for key, or generates and stores one
+	// using generate when absent. Concurrent first use yields one value.
+	Ensure(ctx context.Context, key string, generate func() (string, error)) (string, error)
+}

backend/internal/settings/sqlite_store.go

@@ -0,0 +1,63 @@
+package settings
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+	"time"
+
+	"shared-album/internal/sqliteutil"
+)
+
+// SQLiteStore is the SQLite implementation of Repository.
+type SQLiteStore struct {
+	db *sql.DB
+}
+
+func NewSQLiteStore(db *sql.DB) *SQLiteStore { return &SQLiteStore{db: db} }
+
+func (s *SQLiteStore) Get(ctx context.Context, key string) (string, bool, error) {
+	var v string
+	err := s.db.QueryRowContext(ctx, `SELECT value FROM app_settings WHERE key = $1`, key).Scan(&v)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return "", false, nil
+		}
+		return "", false, err
+	}
+	return v, true, nil
+}
+
+func (s *SQLiteStore) Set(ctx context.Context, key, value string) error {
+	_, err := s.db.ExecContext(ctx,
+		`INSERT INTO app_settings (key, value) VALUES ($1, $2)
+		 ON CONFLICT (key) DO UPDATE SET value = excluded.value, updated_at = $3`,
+		key, value, sqliteutil.FormatTime(time.Now()))
+	return err
+}
+
+func (s *SQLiteStore) Ensure(ctx context.Context, key string, generate func() (string, error)) (string, error) {
+	if v, ok, err := s.Get(ctx, key); err != nil {
+		return "", err
+	} else if ok {
+		return v, nil
+	}
+	v, err := generate()
+	if err != nil {
+		return "", err
+	}
+	if _, err := s.db.ExecContext(ctx,
+		`INSERT INTO app_settings (key, value) VALUES ($1, $2) ON CONFLICT (key) DO NOTHING`,
+		key, v); err != nil {
+		return "", err
+	}
+	got, ok, err := s.Get(ctx, key)
+	if err != nil {
+		return "", err
+	}
+	if !ok {
+		return "", fmt.Errorf("settings: %q missing after insert", key)
+	}
+	return got, nil
+}

backend/internal/settings/store.go

@@ -0,0 +1,62 @@
+package settings
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+// Store is the PostgreSQL implementation of Repository.
+type Store struct {
+	pool *pgxpool.Pool
+}
+
+func NewStore(pool *pgxpool.Pool) *Store { return &Store{pool: pool} }
+
+func (s *Store) Get(ctx context.Context, key string) (string, bool, error) {
+	var v string
+	err := s.pool.QueryRow(ctx, `SELECT value FROM app_settings WHERE key = $1`, key).Scan(&v)
+	if err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return "", false, nil
+		}
+		return "", false, err
+	}
+	return v, true, nil
+}
+
+func (s *Store) Set(ctx context.Context, key, value string) error {
+	_, err := s.pool.Exec(ctx,
+		`INSERT INTO app_settings (key, value) VALUES ($1, $2)
+		 ON CONFLICT (key) DO UPDATE SET value = EXCLUDED.value, updated_at = now()`,
+		key, value)
+	return err
+}
+
+func (s *Store) Ensure(ctx context.Context, key string, generate func() (string, error)) (string, error) {
+	if v, ok, err := s.Get(ctx, key); err != nil {
+		return "", err
+	} else if ok {
+		return v, nil
+	}
+	v, err := generate()
+	if err != nil {
+		return "", err
+	}
+	if _, err := s.pool.Exec(ctx,
+		`INSERT INTO app_settings (key, value) VALUES ($1, $2) ON CONFLICT (key) DO NOTHING`,
+		key, v); err != nil {
+		return "", err
+	}
+	got, ok, err := s.Get(ctx, key)
+	if err != nil {
+		return "", err
+	}
+	if !ok {
+		return "", fmt.Errorf("settings: %q missing after insert", key)
+	}
+	return got, nil
+}

backend/internal/sharelinks/repository.go

@@ -0,0 +1,15 @@
+package sharelinks
+
+import (
+	"context"
+
+	"shared-album/internal/models"
+)
+
+// Repository is the persistence contract for the share-links domain.
+type Repository interface {
+	Create(ctx context.Context, l *models.ShareLink) error
+	ListByAlbum(ctx context.Context, albumID string) ([]models.ShareLink, error)
+	GetByToken(ctx context.Context, token string) (*models.ShareLink, error)
+	Revoke(ctx context.Context, id, albumID string) error
+}

backend/internal/sharelinks/service.go

@@ -16,11 +16,11 @@ type AlbumAccess interface {
 }
 
 type Service struct {
-	store  *Store
+	store  Repository
 	albums AlbumAccess
 }
 
-func NewService(store *Store, albums AlbumAccess) *Service {
+func NewService(store Repository, albums AlbumAccess) *Service {
 	return &Service{store: store, albums: albums}
 }
 

backend/internal/sharelinks/sqlite_store.go

@@ -0,0 +1,90 @@
+package sharelinks
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"time"
+
+	"shared-album/internal/models"
+	"shared-album/internal/sqliteutil"
+)
+
+// SQLiteStore is the SQLite implementation of Repository.
+type SQLiteStore struct {
+	db *sql.DB
+}
+
+func NewSQLiteStore(db *sql.DB) *SQLiteStore { return &SQLiteStore{db: db} }
+
+func (s *SQLiteStore) Create(ctx context.Context, l *models.ShareLink) error {
+	var createdAt string
+	err := s.db.QueryRowContext(ctx,
+		`INSERT INTO share_links (id, album_id, token, created_by, expires_at)
+		 VALUES ($1, $2, $3, $4, $5)
+		 RETURNING created_at`,
+		l.ID, l.AlbumID, l.Token, l.CreatedBy, sqliteutil.FormatTime(l.ExpiresAt),
+	).Scan(&createdAt)
+	if err != nil {
+		return err
+	}
+	l.CreatedAt = sqliteutil.ParseTime(createdAt)
+	return nil
+}
+
+func (s *SQLiteStore) ListByAlbum(ctx context.Context, albumID string) ([]models.ShareLink, error) {
+	rows, err := s.db.QueryContext(ctx,
+		`SELECT id, album_id, token, created_by, created_at, expires_at, revoked_at
+		 FROM share_links WHERE album_id = $1 ORDER BY created_at DESC`, albumID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	out := []models.ShareLink{}
+	for rows.Next() {
+		var l models.ShareLink
+		var createdAt, expiresAt string
+		var revokedAt sql.NullString
+		if err := rows.Scan(&l.ID, &l.AlbumID, &l.Token, &l.CreatedBy, &createdAt, &expiresAt, &revokedAt); err != nil {
+			return nil, err
+		}
+		l.CreatedAt = sqliteutil.ParseTime(createdAt)
+		l.ExpiresAt = sqliteutil.ParseTime(expiresAt)
+		l.RevokedAt = sqliteutil.ParseNullTime(revokedAt)
+		out = append(out, l)
+	}
+	return out, rows.Err()
+}
+
+func (s *SQLiteStore) GetByToken(ctx context.Context, token string) (*models.ShareLink, error) {
+	var l models.ShareLink
+	var createdAt, expiresAt string
+	var revokedAt sql.NullString
+	err := s.db.QueryRowContext(ctx,
+		`SELECT id, album_id, token, created_by, created_at, expires_at, revoked_at
+		 FROM share_links WHERE token = $1`, token).
+		Scan(&l.ID, &l.AlbumID, &l.Token, &l.CreatedBy, &createdAt, &expiresAt, &revokedAt)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, ErrNotFound
+		}
+		return nil, err
+	}
+	l.CreatedAt = sqliteutil.ParseTime(createdAt)
+	l.ExpiresAt = sqliteutil.ParseTime(expiresAt)
+	l.RevokedAt = sqliteutil.ParseNullTime(revokedAt)
+	return &l, nil
+}
+
+func (s *SQLiteStore) Revoke(ctx context.Context, id, albumID string) error {
+	res, err := s.db.ExecContext(ctx,
+		`UPDATE share_links SET revoked_at = $3 WHERE id = $1 AND album_id = $2 AND revoked_at IS NULL`,
+		id, albumID, sqliteutil.FormatTime(time.Now()))
+	if err != nil {
+		return err
+	}
+	if n, _ := res.RowsAffected(); n == 0 {
+		return ErrNotFound
+	}
+	return nil
+}

backend/internal/social/repository.go

@@ -0,0 +1,17 @@
+package social
+
+import (
+	"context"
+
+	"shared-album/internal/models"
+)
+
+// Repository is the persistence contract for the social domain.
+type Repository interface {
+	Like(ctx context.Context, photoID, userID string) error
+	Unlike(ctx context.Context, photoID, userID string) error
+	CreateComment(ctx context.Context, c *models.Comment) error
+	ListComments(ctx context.Context, photoID string) ([]models.Comment, error)
+	GetComment(ctx context.Context, id string) (*models.Comment, error)
+	DeleteComment(ctx context.Context, id string) error
+}

backend/internal/social/service.go

@@ -25,14 +25,14 @@ type Notifier interface {
 }
 
 type Service struct {
-	store  *Store
+	store  Repository
 	albums AlbumAccess
 	photos PhotoLookup
 	hub    *sse.Hub
 	notify Notifier
 }
 
-func NewService(store *Store, albums AlbumAccess, photos PhotoLookup, hub *sse.Hub, notify Notifier) *Service {
+func NewService(store Repository, albums AlbumAccess, photos PhotoLookup, hub *sse.Hub, notify Notifier) *Service {
 	return &Service{store: store, albums: albums, photos: photos, hub: hub, notify: notify}
 }
 

backend/internal/social/sqlite_store.go

@@ -0,0 +1,101 @@
+package social
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+
+	"shared-album/internal/models"
+	"shared-album/internal/sqliteutil"
+)
+
+// SQLiteStore is the SQLite implementation of Repository.
+type SQLiteStore struct {
+	db *sql.DB
+}
+
+func NewSQLiteStore(db *sql.DB) *SQLiteStore { return &SQLiteStore{db: db} }
+
+func (s *SQLiteStore) Like(ctx context.Context, photoID, userID string) error {
+	_, err := s.db.ExecContext(ctx,
+		`INSERT INTO likes (photo_id, user_id) VALUES ($1, $2)
+		 ON CONFLICT (photo_id, user_id) DO NOTHING`, photoID, userID)
+	return err
+}
+
+func (s *SQLiteStore) Unlike(ctx context.Context, photoID, userID string) error {
+	_, err := s.db.ExecContext(ctx,
+		`DELETE FROM likes WHERE photo_id = $1 AND user_id = $2`, photoID, userID)
+	return err
+}
+
+func (s *SQLiteStore) CreateComment(ctx context.Context, c *models.Comment) error {
+	var createdAt, updatedAt string
+	err := s.db.QueryRowContext(ctx,
+		`INSERT INTO comments (id, photo_id, user_id, text)
+		 VALUES ($1, $2, $3, $4)
+		 RETURNING created_at, updated_at`,
+		c.ID, c.PhotoID, c.UserID, c.Text,
+	).Scan(&createdAt, &updatedAt)
+	if err != nil {
+		return err
+	}
+	c.CreatedAt = sqliteutil.ParseTime(createdAt)
+	c.UpdatedAt = sqliteutil.ParseTime(updatedAt)
+	return nil
+}
+
+func (s *SQLiteStore) ListComments(ctx context.Context, photoID string) ([]models.Comment, error) {
+	rows, err := s.db.QueryContext(ctx,
+		`SELECT c.id, c.photo_id, c.user_id, c.text, c.created_at, c.updated_at,
+		        u.id, u.name, COALESCE(u.avatar_url, '')
+		 FROM comments c
+		 JOIN users u ON u.id = c.user_id
+		 WHERE c.photo_id = $1
+		 ORDER BY c.created_at`, photoID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	out := []models.Comment{}
+	for rows.Next() {
+		var c models.Comment
+		var createdAt, updatedAt string
+		if err := rows.Scan(&c.ID, &c.PhotoID, &c.UserID, &c.Text, &createdAt, &updatedAt,
+			&c.User.ID, &c.User.Name, &c.User.AvatarURL); err != nil {
+			return nil, err
+		}
+		c.CreatedAt = sqliteutil.ParseTime(createdAt)
+		c.UpdatedAt = sqliteutil.ParseTime(updatedAt)
+		out = append(out, c)
+	}
+	return out, rows.Err()
+}
+
+func (s *SQLiteStore) GetComment(ctx context.Context, id string) (*models.Comment, error) {
+	var c models.Comment
+	var createdAt, updatedAt string
+	err := s.db.QueryRowContext(ctx,
+		`SELECT id, photo_id, user_id, text, created_at, updated_at FROM comments WHERE id = $1`, id).
+		Scan(&c.ID, &c.PhotoID, &c.UserID, &c.Text, &createdAt, &updatedAt)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, ErrNotFound
+		}
+		return nil, err
+	}
+	c.CreatedAt = sqliteutil.ParseTime(createdAt)
+	c.UpdatedAt = sqliteutil.ParseTime(updatedAt)
+	return &c, nil
+}
+
+func (s *SQLiteStore) DeleteComment(ctx context.Context, id string) error {
+	res, err := s.db.ExecContext(ctx, `DELETE FROM comments WHERE id = $1`, id)
+	if err != nil {
+		return err
+	}
+	if n, _ := res.RowsAffected(); n == 0 {
+		return ErrNotFound
+	}
+	return nil
+}

backend/internal/sqliteutil/sqliteutil.go

@@ -0,0 +1,50 @@
+// Package sqliteutil holds small helpers shared by the SQLite repositories:
+// timestamp conversion and dynamic IN-lists.
+package sqliteutil
+
+import (
+	"database/sql"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// TimeLayout matches the SQLite column defaults produced by strftime with %f.
+const TimeLayout = "2006-01-02T15:04:05.000Z"
+
+// FormatTime renders a time in the canonical TEXT format used by the schema.
+func FormatTime(t time.Time) string { return t.UTC().Format(TimeLayout) }
+
+// ParseTime parses a canonical timestamp, tolerating the RFC3339 variants the
+// driver may return. An empty or unparseable value yields the zero time.
+func ParseTime(s string) time.Time {
+	if s == "" {
+		return time.Time{}
+	}
+	if t, err := time.Parse(TimeLayout, s); err == nil {
+		return t
+	}
+	if t, err := time.Parse(time.RFC3339Nano, s); err == nil {
+		return t
+	}
+	return time.Time{}
+}
+
+// ParseNullTime converts a nullable TEXT timestamp into *time.Time.
+func ParseNullTime(ns sql.NullString) *time.Time {
+	if !ns.Valid || ns.String == "" {
+		return nil
+	}
+	t := ParseTime(ns.String)
+	return &t
+}
+
+// Placeholders returns an IN-list placeholder group of n items starting at
+// index start, e.g. Placeholders(3, 2) -> "$3,$4".
+func Placeholders(start, n int) string {
+	parts := make([]string, n)
+	for i := 0; i < n; i++ {
+		parts[i] = "$" + strconv.Itoa(start+i)
+	}
+	return strings.Join(parts, ",")
+}

backend/internal/storage/fs.go

@@ -0,0 +1,233 @@
+package storage
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"io/fs"
+	"mime"
+	"net/http"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// errInvalidKey is returned for object keys that are empty, absolute or attempt
+// to escape the storage root.
+var errInvalidKey = errors.New("fs: invalid object key")
+
+// FS is a Backend backed by a local directory tree. Blobs live under Root at the
+// path formed by the opaque key. Because a local directory has no external URL,
+// FS serves blobs through the app using the shared Signer.
+type FS struct {
+	root   string
+	signer *Signer
+}
+
+// NewFS builds a local file-system storage backend rooted at root. signer issues
+// and validates the app URLs used to serve blobs.
+func NewFS(root string, signer *Signer) (*FS, error) {
+	if strings.TrimSpace(root) == "" {
+		return nil, errors.New("fs: root is required")
+	}
+	if signer == nil {
+		return nil, errors.New("fs: signer is required")
+	}
+	abs, err := filepath.Abs(root)
+	if err != nil {
+		return nil, fmt.Errorf("fs: resolve root: %w", err)
+	}
+	if err := os.MkdirAll(abs, 0o755); err != nil {
+		return nil, fmt.Errorf("fs: create root: %w", err)
+	}
+	return &FS{root: abs, signer: signer}, nil
+}
+
+func (f *FS) Bucket() string { return f.root }
+
+func (f *FS) EnsureBucket(context.Context) error {
+	return os.MkdirAll(f.root, 0o755)
+}
+
+func (f *FS) Ping(context.Context) error {
+	info, err := os.Stat(f.root)
+	if err != nil {
+		return err
+	}
+	if !info.IsDir() {
+		return errors.New("fs: root is not a directory")
+	}
+	return nil
+}
+
+// objectPath maps an opaque key to an absolute path inside the root, rejecting
+// absolute keys and any key that resolves outside the root.
+func (f *FS) objectPath(key string) (string, error) {
+	if key == "" || filepath.IsAbs(key) {
+		return "", errInvalidKey
+	}
+	clean := filepath.Clean(key)
+	if clean == ".." || strings.HasPrefix(clean, ".."+string(os.PathSeparator)) {
+		return "", errInvalidKey
+	}
+	p := filepath.Join(f.root, clean)
+	rel, err := filepath.Rel(f.root, p)
+	if err != nil || rel == ".." || strings.HasPrefix(rel, ".."+string(os.PathSeparator)) {
+		return "", errInvalidKey
+	}
+	return p, nil
+}
+
+func (f *FS) Put(_ context.Context, key string, body io.Reader, _ int64, _ string) error {
+	p, err := f.objectPath(key)
+	if err != nil {
+		return err
+	}
+	if err := os.MkdirAll(filepath.Dir(p), 0o755); err != nil {
+		return fmt.Errorf("fs: mkdir: %w", err)
+	}
+	tmp, err := os.CreateTemp(filepath.Dir(p), ".upload-*")
+	if err != nil {
+		return fmt.Errorf("fs: temp file: %w", err)
+	}
+	tmpName := tmp.Name()
+	defer func() { _ = os.Remove(tmpName) }()
+	if _, err := io.Copy(tmp, body); err != nil {
+		_ = tmp.Close()
+		return fmt.Errorf("fs: write: %w", err)
+	}
+	if err := tmp.Close(); err != nil {
+		return fmt.Errorf("fs: close: %w", err)
+	}
+	if err := os.Rename(tmpName, p); err != nil {
+		return fmt.Errorf("fs: rename: %w", err)
+	}
+	return nil
+}
+
+func (f *FS) Get(_ context.Context, key string) ([]byte, error) {
+	p, err := f.objectPath(key)
+	if err != nil {
+		return nil, err
+	}
+	data, err := os.ReadFile(p)
+	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return nil, ErrObjectNotFound
+		}
+		return nil, err
+	}
+	return data, nil
+}
+
+func (f *FS) Delete(_ context.Context, keys ...string) error {
+	var errs []error
+	for _, key := range keys {
+		p, err := f.objectPath(key)
+		if err != nil {
+			errs = append(errs, err)
+			continue
+		}
+		if err := os.Remove(p); err != nil && !errors.Is(err, os.ErrNotExist) {
+			errs = append(errs, err)
+		}
+	}
+	return errors.Join(errs...)
+}
+
+// URL returns a signed app URL served by this process.
+func (f *FS) URL(_ context.Context, key string) (string, error) {
+	if _, err := f.objectPath(key); err != nil {
+		return "", err
+	}
+	return f.signer.URL(key), nil
+}
+
+// List returns every blob under prefix as a key relative to the storage root.
+func (f *FS) List(_ context.Context, prefix string) ([]ObjectInfo, error) {
+	var out []ObjectInfo
+	err := filepath.WalkDir(f.root, func(path string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		if d.IsDir() {
+			return nil
+		}
+		rel, err := filepath.Rel(f.root, path)
+		if err != nil {
+			return err
+		}
+		rel = filepath.ToSlash(rel)
+		if prefix != "" && !strings.HasPrefix(rel, prefix) {
+			return nil
+		}
+		info, err := d.Info()
+		if err != nil {
+			return err
+		}
+		out = append(out, ObjectInfo{Key: rel, Size: info.Size(), ModTime: info.ModTime()})
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+// ServeObject validates the signed URL and serves the blob. It supports range
+// requests and sets the content type from the key extension. It writes the
+// response itself and returns nil on success.
+func (f *FS) ServeObject(w http.ResponseWriter, r *http.Request, key string) error {
+	if unescaped, err := url.PathUnescape(key); err == nil {
+		key = unescaped
+	}
+	if err := f.signer.VerifyRequest(key, r); err != nil {
+		return err
+	}
+	p, err := f.objectPath(key)
+	if err != nil {
+		return ErrSignedURLInvalid
+	}
+	file, err := os.Open(p)
+	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return ErrObjectNotFound
+		}
+		return err
+	}
+	defer file.Close()
+	info, err := file.Stat()
+	if err != nil {
+		return err
+	}
+	w.Header().Set("Content-Type", contentTypeForKey(key))
+	http.ServeContent(w, r, info.Name(), info.ModTime(), file)
+	return nil
+}
+
+var imageContentTypes = map[string]string{
+	".jpg":  "image/jpeg",
+	".jpeg": "image/jpeg",
+	".png":  "image/png",
+	".gif":  "image/gif",
+	".webp": "image/webp",
+	".heic": "image/heic",
+	".heif": "image/heif",
+	".tiff": "image/tiff",
+	".tif":  "image/tiff",
+	".bmp":  "image/bmp",
+	".avif": "image/avif",
+}
+
+func contentTypeForKey(key string) string {
+	ext := strings.ToLower(filepath.Ext(key))
+	if ct, ok := imageContentTypes[ext]; ok {
+		return ct
+	}
+	if ct := mime.TypeByExtension(ext); ct != "" {
+		return ct
+	}
+	return "application/octet-stream"
+}

backend/internal/storage/fs_test.go

@@ -0,0 +1,204 @@
+package storage
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"strconv"
+	"strings"
+	"testing"
+	"time"
+)
+
+func newTestFS(t *testing.T) *FS {
+	t.Helper()
+	signer, err := NewSigner("http://app.test", "test-secret", time.Hour)
+	if err != nil {
+		t.Fatalf("signer: %v", err)
+	}
+	fs, err := NewFS(t.TempDir(), signer)
+	if err != nil {
+		t.Fatalf("new fs: %v", err)
+	}
+	return fs
+}
+
+func TestFSRoundTrip(t *testing.T) {
+	ctx := context.Background()
+	fs := newTestFS(t)
+	key := "objects/abc/original.jpg"
+	data := []byte("hello blob")
+
+	if err := fs.Put(ctx, key, bytes.NewReader(data), int64(len(data)), "image/jpeg"); err != nil {
+		t.Fatalf("put: %v", err)
+	}
+	got, err := fs.Get(ctx, key)
+	if err != nil {
+		t.Fatalf("get: %v", err)
+	}
+	if !bytes.Equal(got, data) {
+		t.Fatalf("get = %q, want %q", got, data)
+	}
+	if err := fs.Delete(ctx, key); err != nil {
+		t.Fatalf("delete: %v", err)
+	}
+	if _, err := fs.Get(ctx, key); !errors.Is(err, ErrObjectNotFound) {
+		t.Fatalf("get after delete = %v, want ErrObjectNotFound", err)
+	}
+}
+
+func TestFSPathTraversalRejected(t *testing.T) {
+	ctx := context.Background()
+	fs := newTestFS(t)
+	for _, key := range []string{"../escape", "../../etc/passwd", "/etc/passwd", ""} {
+		if err := fs.Put(ctx, key, strings.NewReader("x"), 1, "text/plain"); err == nil {
+			t.Errorf("put %q: expected rejection", key)
+		}
+		if _, err := fs.Get(ctx, key); err == nil {
+			t.Errorf("get %q: expected rejection", key)
+		}
+		if _, err := fs.URL(ctx, key); err == nil {
+			t.Errorf("url %q: expected rejection", key)
+		}
+	}
+}
+
+func TestFSURLAndServe(t *testing.T) {
+	ctx := context.Background()
+	fs := newTestFS(t)
+	key := "objects/abc/thumb.webp"
+	if err := fs.Put(ctx, key, strings.NewReader("webp-bytes"), 10, "image/webp"); err != nil {
+		t.Fatalf("put: %v", err)
+	}
+
+	raw, err := fs.URL(ctx, key)
+	if err != nil {
+		t.Fatalf("url: %v", err)
+	}
+	u, err := url.Parse(raw)
+	if err != nil {
+		t.Fatalf("parse url: %v", err)
+	}
+	if !strings.HasPrefix(u.Path, "/api/objects/objects/abc/thumb.webp") {
+		t.Fatalf("unexpected path: %s", u.Path)
+	}
+
+	rec := httptest.NewRecorder()
+	req := httptest.NewRequest(http.MethodGet, raw, nil)
+	if err := fs.ServeObject(rec, req, strings.TrimPrefix(u.Path, "/api/objects/")); err != nil {
+		t.Fatalf("serve: %v", err)
+	}
+	if rec.Code != http.StatusOK {
+		t.Fatalf("status = %d, want 200", rec.Code)
+	}
+	if ct := rec.Header().Get("Content-Type"); ct != "image/webp" {
+		t.Fatalf("content-type = %q, want image/webp", ct)
+	}
+	if rec.Body.String() != "webp-bytes" {
+		t.Fatalf("body = %q", rec.Body.String())
+	}
+}
+
+func TestFSServeExpiredAndForged(t *testing.T) {
+	ctx := context.Background()
+	fs := newTestFS(t)
+	key := "objects/abc/original.jpg"
+	if err := fs.Put(ctx, key, strings.NewReader("x"), 1, "image/jpeg"); err != nil {
+		t.Fatalf("put: %v", err)
+	}
+
+	past := time.Now().Add(-time.Minute).Unix()
+	expired := "/api/objects/" + key + "?e=" + strconv.FormatInt(past, 10) + "&s=" + fs.signer.sign(key, past)
+	rec := httptest.NewRecorder()
+	err := fs.ServeObject(rec, httptest.NewRequest(http.MethodGet, expired, nil), key)
+	if !errors.Is(err, ErrSignedURLInvalid) {
+		t.Fatalf("expired = %v, want ErrSignedURLInvalid", err)
+	}
+
+	future := time.Now().Add(time.Hour).Unix()
+	forged := "/api/objects/" + key + "?e=" + strconv.FormatInt(future, 10) + "&s=deadbeef"
+	rec = httptest.NewRecorder()
+	err = fs.ServeObject(rec, httptest.NewRequest(http.MethodGet, forged, nil), key)
+	if !errors.Is(err, ErrSignedURLInvalid) {
+		t.Fatalf("forged = %v, want ErrSignedURLInvalid", err)
+	}
+}
+
+func TestFSServeRangeAndMissing(t *testing.T) {
+	ctx := context.Background()
+	fs := newTestFS(t)
+	key := "objects/abc/original.jpg"
+	if err := fs.Put(ctx, key, strings.NewReader("0123456789"), 10, "image/jpeg"); err != nil {
+		t.Fatalf("put: %v", err)
+	}
+	exp := time.Now().Add(time.Hour).Unix()
+	base := "/api/objects/" + key + "?e=" + strconv.FormatInt(exp, 10) + "&s=" + fs.signer.sign(key, exp)
+
+	req := httptest.NewRequest(http.MethodGet, base, nil)
+	req.Header.Set("Range", "bytes=2-5")
+	rec := httptest.NewRecorder()
+	if err := fs.ServeObject(rec, req, key); err != nil {
+		t.Fatalf("serve range: %v", err)
+	}
+	if rec.Code != http.StatusPartialContent {
+		t.Fatalf("status = %d, want 206", rec.Code)
+	}
+	if body, _ := io.ReadAll(rec.Body); string(body) != "2345" {
+		t.Fatalf("range body = %q, want 2345", body)
+	}
+
+	missingKey := "objects/def/original.jpg"
+	missing := "/api/objects/" + missingKey + "?e=" + strconv.FormatInt(exp, 10) + "&s=" + fs.signer.sign(missingKey, exp)
+	rec = httptest.NewRecorder()
+	err := fs.ServeObject(rec, httptest.NewRequest(http.MethodGet, missing, nil), missingKey)
+	if !errors.Is(err, ErrObjectNotFound) {
+		t.Fatalf("missing = %v, want ErrObjectNotFound", err)
+	}
+}
+
+func TestContentTypeForKey(t *testing.T) {
+	cases := map[string]string{
+		"objects/a/original.jpg":   "image/jpeg",
+		"objects/a/thumb.webp":     "image/webp",
+		"objects/a/odd.unknownext": "application/octet-stream",
+	}
+	for key, want := range cases {
+		if got := contentTypeForKey(key); got != want {
+			t.Errorf("contentTypeForKey(%q) = %q, want %q", key, got, want)
+		}
+	}
+}
+
+func TestFSList(t *testing.T) {
+	ctx := context.Background()
+	fs := newTestFS(t)
+	for _, key := range []string{"objects/a/original.jpg", "objects/b/original.jpg", "misc/readme.txt"} {
+		if err := fs.Put(ctx, key, strings.NewReader("x"), 1, "text/plain"); err != nil {
+			t.Fatalf("put %s: %v", key, err)
+		}
+	}
+
+	all, err := fs.List(ctx, "")
+	if err != nil || len(all) != 3 {
+		t.Fatalf("list all: %v len=%d", err, len(all))
+	}
+	objs, err := fs.List(ctx, "objects/")
+	if err != nil {
+		t.Fatalf("list objects: %v", err)
+	}
+	if len(objs) != 2 {
+		t.Fatalf("list objects len=%d, want 2", len(objs))
+	}
+	for _, o := range objs {
+		if !strings.HasPrefix(o.Key, "objects/") {
+			t.Fatalf("unexpected key %q", o.Key)
+		}
+		if o.Size != 1 || o.ModTime.IsZero() {
+			t.Fatalf("unexpected info %+v", o)
+		}
+	}
+}

backend/internal/storage/s3_test.go

@@ -0,0 +1,169 @@
+package storage
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"strconv"
+	"strings"
+	"testing"
+	"time"
+
+	"shared-album/internal/config"
+)
+
+func newTestS3(t *testing.T) (*S3, *Signer) {
+	t.Helper()
+	endpoint := os.Getenv("S3_ENDPOINT")
+	if endpoint == "" {
+		t.Skip("S3_ENDPOINT not set")
+	}
+	signer, err := NewSigner("http://app.test", "secret", time.Hour)
+	if err != nil {
+		t.Fatalf("signer: %v", err)
+	}
+	cl, err := NewS3(context.Background(), config.S3{
+		Endpoint:     endpoint,
+		Region:       os.Getenv("S3_REGION"),
+		AccessKey:    os.Getenv("S3_ACCESS_KEY"),
+		SecretKey:    os.Getenv("S3_SECRET_KEY"),
+		Bucket:       os.Getenv("S3_BUCKET"),
+		UsePathStyle: true,
+	}, signer)
+	if err != nil {
+		t.Skipf("storage init: %v", err)
+	}
+	return cl, signer
+}
+
+func signedQuery(signer *Signer, key string, exp int64) string {
+	return "?e=" + strconv.FormatInt(exp, 10) + "&s=" + signer.sign(key, exp)
+}
+
+func TestS3ServeObject(t *testing.T) {
+	ctx := context.Background()
+	cl, signer := newTestS3(t)
+	key := "objects/" + strconv.FormatInt(time.Now().UnixNano(), 10) + "/original.jpg"
+	data := []byte("0123456789")
+	if err := cl.Put(ctx, key, bytes.NewReader(data), int64(len(data)), "image/jpeg"); err != nil {
+		t.Fatalf("put: %v", err)
+	}
+	t.Cleanup(func() { _ = cl.Delete(context.Background(), key) })
+
+	exp := time.Now().Add(time.Hour).Unix()
+	base := "/api/objects/" + key + signedQuery(signer, key, exp)
+
+	t.Run("full", func(t *testing.T) {
+		rec := httptest.NewRecorder()
+		req := httptest.NewRequest(http.MethodGet, base, nil)
+		if err := cl.ServeObject(rec, req, key); err != nil {
+			t.Fatalf("serve: %v", err)
+		}
+		if rec.Code != http.StatusOK {
+			t.Fatalf("status = %d, want 200", rec.Code)
+		}
+		if !bytes.Equal(rec.Body.Bytes(), data) {
+			t.Fatalf("body = %q", rec.Body.String())
+		}
+	})
+
+	t.Run("range", func(t *testing.T) {
+		rec := httptest.NewRecorder()
+		req := httptest.NewRequest(http.MethodGet, base, nil)
+		req.Header.Set("Range", "bytes=2-5")
+		if err := cl.ServeObject(rec, req, key); err != nil {
+			t.Fatalf("serve range: %v", err)
+		}
+		if rec.Code != http.StatusPartialContent {
+			t.Fatalf("status = %d, want 206", rec.Code)
+		}
+		if body, _ := io.ReadAll(rec.Body); string(body) != "2345" {
+			t.Fatalf("range body = %q, want 2345", body)
+		}
+	})
+
+	t.Run("invalid range", func(t *testing.T) {
+		rec := httptest.NewRecorder()
+		req := httptest.NewRequest(http.MethodGet, base, nil)
+		req.Header.Set("Range", "bytes=1000-2000")
+		err := cl.ServeObject(rec, req, key)
+		if !errors.Is(err, ErrRangeNotSatisfiable) {
+			t.Fatalf("err = %v, want ErrRangeNotSatisfiable", err)
+		}
+	})
+
+	t.Run("missing", func(t *testing.T) {
+		missingKey := "objects/" + strconv.FormatInt(time.Now().UnixNano(), 10) + "/original.jpg"
+		target := "/api/objects/" + missingKey + signedQuery(signer, missingKey, exp)
+		rec := httptest.NewRecorder()
+		err := cl.ServeObject(rec, httptest.NewRequest(http.MethodGet, target, nil), missingKey)
+		if !errors.Is(err, ErrObjectNotFound) {
+			t.Fatalf("err = %v, want ErrObjectNotFound", err)
+		}
+	})
+
+	t.Run("expired signature", func(t *testing.T) {
+		past := time.Now().Add(-time.Minute).Unix()
+		target := "/api/objects/" + key + signedQuery(signer, key, past)
+		rec := httptest.NewRecorder()
+		err := cl.ServeObject(rec, httptest.NewRequest(http.MethodGet, target, nil), key)
+		if !errors.Is(err, ErrSignedURLInvalid) {
+			t.Fatalf("err = %v, want ErrSignedURLInvalid", err)
+		}
+	})
+}
+
+func TestS3List(t *testing.T) {
+	ctx := context.Background()
+	cl, _ := newTestS3(t)
+	prefix := "objects/" + strconv.FormatInt(time.Now().UnixNano(), 10) + "/"
+	keys := []string{prefix + "original.jpg", prefix + "thumb.webp"}
+	for _, k := range keys {
+		if err := cl.Put(ctx, k, strings.NewReader("x"), 1, "image/jpeg"); err != nil {
+			t.Fatalf("put %s: %v", k, err)
+		}
+	}
+	t.Cleanup(func() { _ = cl.Delete(context.Background(), keys...) })
+
+	got, err := cl.List(ctx, prefix)
+	if err != nil {
+		t.Fatalf("list: %v", err)
+	}
+	found := map[string]bool{}
+	for _, o := range got {
+		found[o.Key] = true
+	}
+	for _, k := range keys {
+		if !found[k] {
+			t.Fatalf("key %s not listed: %+v", k, got)
+		}
+	}
+}
+
+func TestS3ServeObjectHead(t *testing.T) {
+	ctx := context.Background()
+	cl, signer := newTestS3(t)
+	key := "objects/" + strconv.FormatInt(time.Now().UnixNano(), 10) + "/original.jpg"
+	data := []byte("head-check")
+	if err := cl.Put(ctx, key, strings.NewReader(string(data)), int64(len(data)), "image/jpeg"); err != nil {
+		t.Fatalf("put: %v", err)
+	}
+	t.Cleanup(func() { _ = cl.Delete(context.Background(), key) })
+
+	exp := time.Now().Add(time.Hour).Unix()
+	target := "/api/objects/" + key + signedQuery(signer, key, exp)
+	rec := httptest.NewRecorder()
+	if err := cl.ServeObject(rec, httptest.NewRequest(http.MethodHead, target, nil), key); err != nil {
+		t.Fatalf("head: %v", err)
+	}
+	if rec.Code != http.StatusOK {
+		t.Fatalf("status = %d, want 200", rec.Code)
+	}
+	if rec.Body.Len() != 0 {
+		t.Fatalf("HEAD body should be empty, got %d bytes", rec.Body.Len())
+	}
+}

backend/internal/storage/signer.go

@@ -0,0 +1,80 @@
+package storage
+
+import (
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// Signer produces and verifies the signed app URLs used by the /api/objects
+// route. It is shared by every storage backend so delivery is identical: the
+// client always talks to the backend, never to object storage directly.
+type Signer struct {
+	secret  []byte
+	baseURL string
+	ttl     time.Duration
+}
+
+// NewSigner builds a signer. secret signs the URLs (required); baseURL is the
+// public base URL of the app; ttl limits URL lifetime (defaults to one hour).
+func NewSigner(baseURL, secret string, ttl time.Duration) (*Signer, error) {
+	if strings.TrimSpace(secret) == "" {
+		return nil, errors.New("url secret is required")
+	}
+	if ttl <= 0 {
+		ttl = time.Hour
+	}
+	return &Signer{
+		secret:  []byte(secret),
+		baseURL: strings.TrimRight(baseURL, "/"),
+		ttl:     ttl,
+	}, nil
+}
+
+// URL returns a signed app URL for the given opaque key.
+func (s *Signer) URL(key string) string {
+	exp := time.Now().Add(s.ttl).Unix()
+	q := url.Values{}
+	q.Set("e", strconv.FormatInt(exp, 10))
+	q.Set("s", s.sign(key, exp))
+	return fmt.Sprintf("%s/api/objects/%s?%s", s.baseURL, escapeKey(key), q.Encode())
+}
+
+// VerifyRequest checks the signature and expiry carried by an object request.
+// It returns ErrSignedURLInvalid when the request is not authorized.
+func (s *Signer) VerifyRequest(key string, r *http.Request) error {
+	q := r.URL.Query()
+	exp, err := strconv.ParseInt(q.Get("e"), 10, 64)
+	if err != nil || !s.verify(key, exp, q.Get("s")) {
+		return ErrSignedURLInvalid
+	}
+	return nil
+}
+
+func (s *Signer) sign(key string, exp int64) string {
+	mac := hmac.New(sha256.New, s.secret)
+	_, _ = fmt.Fprintf(mac, "%s\n%d", key, exp)
+	return hex.EncodeToString(mac.Sum(nil))
+}
+
+func (s *Signer) verify(key string, exp int64, sig string) bool {
+	if sig == "" || time.Now().Unix() > exp {
+		return false
+	}
+	return hmac.Equal([]byte(s.sign(key, exp)), []byte(sig))
+}
+
+func escapeKey(key string) string {
+	parts := strings.Split(key, "/")
+	for i, p := range parts {
+		parts[i] = url.PathEscape(p)
+	}
+	return strings.Join(parts, "/")
+}

backend/internal/storage/storage.go

@@ -5,6 +5,8 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"net/http"
+	"strconv"
 	"strings"
 	"time"
 
@@ -18,14 +20,58 @@ import (
 	"shared-album/internal/config"
 )
 
-type Client struct {
-	s3         *s3.Client
-	presign    *s3.PresignClient
-	bucket     string
-	presignTTL time.Duration
+// ErrSignedURLInvalid is returned when an app-served object URL has a missing,
+// malformed, expired or forged signature.
+var ErrSignedURLInvalid = errors.New("invalid or expired object signature")
+
+// ErrObjectNotFound is returned when the requested blob does not exist.
+var ErrObjectNotFound = errors.New("object not found")
+
+// ErrRangeNotSatisfiable is returned when a requested byte range is invalid.
+var ErrRangeNotSatisfiable = errors.New("requested range not satisfiable")
+
+// ObjectInfo describes one stored blob for inventory and reconciliation.
+type ObjectInfo struct {
+	Key     string
+	Size    int64
+	ModTime time.Time
 }
 
-func New(ctx context.Context, cfg config.S3) (*Client, error) {
+// Backend is the object storage abstraction. Keys are opaque and independent of
+// the backend: every implementation stores and serves the same logical blob.
+// Blobs are always delivered through the app.
+type Backend interface {
+	Put(ctx context.Context, key string, body io.Reader, size int64, contentType string) error
+	Delete(ctx context.Context, keys ...string) error
+	Get(ctx context.Context, key string) ([]byte, error)
+	// URL returns a time-limited signed app URL the client can use to fetch the blob.
+	URL(ctx context.Context, key string) (string, error)
+	// ServeObject validates the signed URL and writes the blob, including
+	// Content-Type and range handling, to the response.
+	ServeObject(w http.ResponseWriter, r *http.Request, key string) error
+	// List returns the blobs under prefix for inventory and reconciliation.
+	List(ctx context.Context, prefix string) ([]ObjectInfo, error)
+	Ping(ctx context.Context) error
+	EnsureBucket(ctx context.Context) error
+	// Bucket returns a human-readable identifier for the storage location.
+	Bucket() string
+}
+
+// S3 is a Backend backed by an S3-compatible object store (Garage). Blobs are
+// delivered through the app: the client receives a signed app URL and the bytes
+// are streamed from S3 over the internal network.
+type S3 struct {
+	s3     *s3.Client
+	bucket string
+	signer *Signer
+}
+
+// NewS3 builds an S3-compatible storage backend. signer issues the app URLs used
+// to serve blobs.
+func NewS3(ctx context.Context, cfg config.S3, signer *Signer) (*S3, error) {
+	if signer == nil {
+		return nil, errors.New("s3: signer is required")
+	}
 	awsCfg, err := awsconfig.LoadDefaultConfig(ctx,
 		awsconfig.WithRegion(cfg.Region),
 		awsconfig.WithCredentialsProvider(credentials.NewStaticCredentialsProvider(
@@ -41,17 +87,42 @@ func New(ctx context.Context, cfg config.S3) (*Client, error) {
 		o.UsePathStyle = cfg.UsePathStyle
 	})
 
-	return &Client{
+	return &S3{
 		s3:     client,
-		presign:    s3.NewPresignClient(client),
 		bucket: cfg.Bucket,
-		presignTTL: cfg.PresignTTL,
+		signer: signer,
 	}, nil
 }
 
-func (c *Client) Bucket() string { return c.bucket }
+func (c *S3) Bucket() string { return c.bucket }
 
-func (c *Client) EnsureBucket(ctx context.Context) error {
+// Open builds the storage backend selected by configuration: S3-compatible by
+// default, or the local file system when STORAGE_BACKEND=fs. Every backend
+// delivers blobs through the app using a shared Signer. jwtSecret is the
+// application secret used to sign object URLs when URL_SECRET is not set.
+func Open(ctx context.Context, cfg *config.Config, jwtSecret string) (Backend, error) {
+	secret := cfg.Storage.URLSecret
+	if secret == "" {
+		secret = jwtSecret
+	}
+	if secret == "" {
+		return nil, errors.New("object URL secret is not available")
+	}
+	signer, err := NewSigner(cfg.Server.BaseURL, secret, cfg.Storage.URLTTL)
+	if err != nil {
+		return nil, err
+	}
+	switch cfg.Storage.Backend {
+	case "", "s3":
+		return NewS3(ctx, cfg.S3, signer)
+	case "fs":
+		return NewFS(cfg.Storage.FSRoot, signer)
+	default:
+		return nil, fmt.Errorf("unknown storage backend %q", cfg.Storage.Backend)
+	}
+}
+
+func (c *S3) EnsureBucket(ctx context.Context) error {
 	_, err := c.s3.HeadBucket(ctx, &s3.HeadBucketInput{Bucket: aws.String(c.bucket)})
 	if err == nil {
 		return nil
@@ -66,12 +137,12 @@ func (c *Client) EnsureBucket(ctx context.Context) error {
 	return nil
 }
 
-func (c *Client) Ping(ctx context.Context) error {
+func (c *S3) Ping(ctx context.Context) error {
 	_, err := c.s3.HeadBucket(ctx, &s3.HeadBucketInput{Bucket: aws.String(c.bucket)})
 	return err
 }
 
-func (c *Client) Put(ctx context.Context, key string, body io.Reader, size int64, contentType string) error {
+func (c *S3) Put(ctx context.Context, key string, body io.Reader, size int64, contentType string) error {
 	in := &s3.PutObjectInput{
 		Bucket:      aws.String(c.bucket),
 		Key:         aws.String(key),
@@ -87,7 +158,7 @@ func (c *Client) Put(ctx context.Context, key string, body io.Reader, size int64
 	return nil
 }
 
-func (c *Client) Delete(ctx context.Context, keys ...string) error {
+func (c *S3) Delete(ctx context.Context, keys ...string) error {
 	if len(keys) == 0 {
 		return nil
 	}
@@ -104,25 +175,7 @@ func (c *Client) Delete(ctx context.Context, keys ...string) error {
 	return nil
 }
 
-func (c *Client) DeletePrefix(ctx context.Context, prefix string) error {
-	var keys []string
-	paginator := s3.NewListObjectsV2Paginator(c.s3, &s3.ListObjectsV2Input{
-		Bucket: aws.String(c.bucket),
-		Prefix: aws.String(prefix),
-	})
-	for paginator.HasMorePages() {
-		page, err := paginator.NextPage(ctx)
-		if err != nil {
-			return fmt.Errorf("list objects: %w", err)
-		}
-		for _, o := range page.Contents {
-			keys = append(keys, aws.ToString(o.Key))
-		}
-	}
-	return c.Delete(ctx, keys...)
-}
-
-func (c *Client) Get(ctx context.Context, key string) ([]byte, error) {
+func (c *S3) Get(ctx context.Context, key string) ([]byte, error) {
 	out, err := c.s3.GetObject(ctx, &s3.GetObjectInput{
 		Bucket: aws.String(c.bucket),
 		Key:    aws.String(key),
@@ -138,14 +191,127 @@ func (c *Client) Get(ctx context.Context, key string) ([]byte, error) {
 	return data, nil
 }
 
-func (c *Client) PresignGet(ctx context.Context, key string) (string, error) {	out, err := c.presign.PresignGetObject(ctx, &s3.GetObjectInput{
+// URL returns a signed app URL. The blob itself is streamed by ServeObject, so
+// the S3 endpoint is never exposed to the client.
+func (c *S3) URL(_ context.Context, key string) (string, error) {
+	return c.signer.URL(key), nil
+}
+
+// List returns every object under prefix using paginated ListObjectsV2.
+func (c *S3) List(ctx context.Context, prefix string) ([]ObjectInfo, error) {
+	var out []ObjectInfo
+	var token *string
+	for {
+		in := &s3.ListObjectsV2Input{Bucket: aws.String(c.bucket)}
+		if prefix != "" {
+			in.Prefix = aws.String(prefix)
+		}
+		if token != nil {
+			in.ContinuationToken = token
+		}
+		res, err := c.s3.ListObjectsV2(ctx, in)
+		if err != nil {
+			return nil, fmt.Errorf("list objects: %w", err)
+		}
+		for _, o := range res.Contents {
+			out = append(out, ObjectInfo{
+				Key:     aws.ToString(o.Key),
+				Size:    aws.ToInt64(o.Size),
+				ModTime: aws.ToTime(o.LastModified),
+			})
+		}
+		if res.IsTruncated == nil || !*res.IsTruncated {
+			return out, nil
+		}
+		token = res.NextContinuationToken
+	}
+}
+
+// ServeObject validates the signed URL and streams the blob from S3. It passes
+// the client's Range header through to S3, so byte ranges are handled natively,
+// and answers HEAD via HeadObject. It writes the response itself.
+func (c *S3) ServeObject(w http.ResponseWriter, r *http.Request, key string) error {
+	if err := c.signer.VerifyRequest(key, r); err != nil {
+		return err
+	}
+	if r.Method == http.MethodHead {
+		return c.headObject(w, r, key)
+	}
+	in := &s3.GetObjectInput{Bucket: aws.String(c.bucket), Key: aws.String(key)}
+	if rng := r.Header.Get("Range"); rng != "" {
+		in.Range = aws.String(rng)
+	}
+	out, err := c.s3.GetObject(r.Context(), in)
+	if err != nil {
+		if isNoSuchKey(err) {
+			return ErrObjectNotFound
+		}
+		if isInvalidRange(err) {
+			return ErrRangeNotSatisfiable
+		}
+		return err
+	}
+	defer out.Body.Close()
+	if ct := aws.ToString(out.ContentType); ct != "" {
+		w.Header().Set("Content-Type", ct)
+	} else {
+		w.Header().Set("Content-Type", contentTypeForKey(key))
+	}
+	if out.ContentLength != nil {
+		w.Header().Set("Content-Length", strconv.FormatInt(*out.ContentLength, 10))
+	}
+	if out.ContentRange != nil {
+		w.Header().Set("Content-Range", *out.ContentRange)
+	}
+	status := http.StatusOK
+	if out.ContentRange != nil {
+		status = http.StatusPartialContent
+	}
+	w.WriteHeader(status)
+	if _, err := io.Copy(w, out.Body); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (c *S3) headObject(w http.ResponseWriter, r *http.Request, key string) error {
+	out, err := c.s3.HeadObject(r.Context(), &s3.HeadObjectInput{
 		Bucket: aws.String(c.bucket),
 		Key:    aws.String(key),
-	}, s3.WithPresignExpires(c.presignTTL))
+	})
 	if err != nil {
-		return "", fmt.Errorf("presign %s: %w", key, err)
+		if isNoSuchKey(err) {
+			return ErrObjectNotFound
 		}
-	return out.URL, nil
+		return err
+	}
+	if ct := aws.ToString(out.ContentType); ct != "" {
+		w.Header().Set("Content-Type", ct)
+	} else {
+		w.Header().Set("Content-Type", contentTypeForKey(key))
+	}
+	if out.ContentLength != nil {
+		w.Header().Set("Content-Length", strconv.FormatInt(*out.ContentLength, 10))
+	}
+	w.WriteHeader(http.StatusOK)
+	return nil
+}
+
+func isNoSuchKey(err error) bool {
+	var apiErr smithy.APIError
+	if errors.As(err, &apiErr) {
+		code := apiErr.ErrorCode()
+		return strings.EqualFold(code, "NoSuchKey") || strings.EqualFold(code, "NotFound")
+	}
+	return false
+}
+
+func isInvalidRange(err error) bool {
+	var apiErr smithy.APIError
+	if errors.As(err, &apiErr) {
+		return strings.EqualFold(apiErr.ErrorCode(), "InvalidRange")
+	}
+	return false
 }
 
 func isNoSuchBucket(err error) bool {

backend/internal/store/store.go

@@ -0,0 +1,59 @@
+// Package store builds the per-domain metadata repositories for a chosen
+// backend. Domains depend on their Repository interfaces; this factory is the
+// single place that knows the concrete implementations.
+package store
+
+import (
+	"database/sql"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+
+	"shared-album/internal/albums"
+	"shared-album/internal/auth"
+	"shared-album/internal/members"
+	"shared-album/internal/notifications"
+	"shared-album/internal/photos"
+	"shared-album/internal/settings"
+	"shared-album/internal/sharelinks"
+	"shared-album/internal/social"
+)
+
+// Repos bundles one repository per domain.
+type Repos struct {
+	Auth          auth.Repository
+	Albums        albums.Repository
+	Members       members.Repository
+	Photos        photos.Repository
+	Social        social.Repository
+	Notifications notifications.Repository
+	ShareLinks    sharelinks.Repository
+	Settings      settings.Repository
+}
+
+// NewPostgres builds the repositories backed by PostgreSQL.
+func NewPostgres(pool *pgxpool.Pool) Repos {
+	return Repos{
+		Auth:          auth.NewStore(pool),
+		Albums:        albums.NewStore(pool),
+		Members:       members.NewStore(pool),
+		Photos:        photos.NewStore(pool),
+		Social:        social.NewStore(pool),
+		Notifications: notifications.NewStore(pool),
+		ShareLinks:    sharelinks.NewStore(pool),
+		Settings:      settings.NewStore(pool),
+	}
+}
+
+// NewSQLite builds the repositories backed by SQLite.
+func NewSQLite(db *sql.DB) Repos {
+	return Repos{
+		Auth:          auth.NewSQLiteStore(db),
+		Albums:        albums.NewSQLiteStore(db),
+		Members:       members.NewSQLiteStore(db),
+		Photos:        photos.NewSQLiteStore(db),
+		Social:        social.NewSQLiteStore(db),
+		Notifications: notifications.NewSQLiteStore(db),
+		ShareLinks:    sharelinks.NewSQLiteStore(db),
+		Settings:      settings.NewSQLiteStore(db),
+	}
+}

backend/internal/store/store_test.go

@@ -0,0 +1,55 @@
+package store
+
+import (
+	"context"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+
+	assets "shared-album"
+	"shared-album/internal/db"
+)
+
+func assertComplete(t *testing.T, r Repos) {
+	t.Helper()
+	if r.Auth == nil || r.Albums == nil || r.Members == nil || r.Photos == nil ||
+		r.Social == nil || r.Notifications == nil || r.ShareLinks == nil {
+		t.Fatalf("incomplete repository bundle: %+v", r)
+	}
+}
+
+func TestNewSQLite(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "meta.db")
+	migFS, err := fs.Sub(assets.Migrations, "migrations/sqlite")
+	if err != nil {
+		t.Fatalf("migrations fs: %v", err)
+	}
+	if err := db.MigrateSQLite(path, migFS); err != nil {
+		t.Fatalf("migrate: %v", err)
+	}
+	database, err := db.OpenSQLite(path)
+	if err != nil {
+		t.Fatalf("open: %v", err)
+	}
+	defer database.Close()
+	assertComplete(t, NewSQLite(database))
+}
+
+func TestNewPostgres(t *testing.T) {
+	dsn := os.Getenv("TEST_DATABASE_URL")
+	if dsn == "" {
+		t.Skip("TEST_DATABASE_URL not set")
+	}
+	pool, err := pgxpool.New(context.Background(), dsn)
+	if err != nil {
+		t.Skipf("cannot connect: %v", err)
+	}
+	if err := pool.Ping(context.Background()); err != nil {
+		t.Skipf("cannot ping: %v", err)
+	}
+	t.Cleanup(pool.Close)
+	assertComplete(t, NewPostgres(pool))
+}

backend/migrations/000008_media_objects.down.sql

@@ -0,0 +1,3 @@
+DROP TABLE IF EXISTS variant_jobs;
+DROP TABLE IF EXISTS photo_objects;
+DROP TABLE IF EXISTS objects;

backend/migrations/000008_media_objects.up.sql

@@ -0,0 +1,39 @@
+-- Physical objects stored in S3. Keys are opaque and never encode album, photo
+-- or any other metadata entity. The row is the ledger entry that governs the
+-- lifecycle of the corresponding blob.
+CREATE TABLE IF NOT EXISTS objects (
+    id          text PRIMARY KEY,
+    storage_key text NOT NULL UNIQUE,
+    mime_type   text NOT NULL DEFAULT '',
+    size        bigint NOT NULL DEFAULT 0,
+    width       integer NOT NULL DEFAULT 0,
+    height      integer NOT NULL DEFAULT 0,
+    checksum    text NOT NULL DEFAULT '',
+    state       text NOT NULL DEFAULT 'pending'
+        CHECK (state IN ('pending', 'ready', 'deleting')),
+    created_at  timestamptz NOT NULL DEFAULT now()
+);
+
+CREATE INDEX IF NOT EXISTS objects_state_created_idx ON objects (state, created_at);
+
+-- Binding of a photo to its objects by role. The role is a property of the
+-- binding, not of the object itself.
+CREATE TABLE IF NOT EXISTS photo_objects (
+    photo_id  text NOT NULL REFERENCES photos(id) ON DELETE CASCADE,
+    object_id text NOT NULL REFERENCES objects(id) ON DELETE RESTRICT,
+    role      text NOT NULL CHECK (role IN ('original', 'thumb', 'preview')),
+    PRIMARY KEY (photo_id, role)
+);
+
+CREATE INDEX IF NOT EXISTS photo_objects_object_idx ON photo_objects (object_id);
+
+-- Durable queue of pending variant generation work, one job per photo.
+CREATE TABLE IF NOT EXISTS variant_jobs (
+    photo_id        text PRIMARY KEY REFERENCES photos(id) ON DELETE CASCADE,
+    attempts        integer NOT NULL DEFAULT 0,
+    next_attempt_at timestamptz NOT NULL DEFAULT now(),
+    last_error      text NOT NULL DEFAULT '',
+    created_at      timestamptz NOT NULL DEFAULT now()
+);
+
+CREATE INDEX IF NOT EXISTS variant_jobs_due_idx ON variant_jobs (next_attempt_at);

backend/migrations/000009_drop_photo_keys.down.sql

@@ -0,0 +1,8 @@
+ALTER TABLE photos
+    ADD COLUMN IF NOT EXISTS storage_key text NOT NULL DEFAULT '',
+    ADD COLUMN IF NOT EXISTS thumb_key text,
+    ADD COLUMN IF NOT EXISTS preview_key text,
+    ADD COLUMN IF NOT EXISTS size bigint NOT NULL DEFAULT 0,
+    ADD COLUMN IF NOT EXISTS width integer NOT NULL DEFAULT 0,
+    ADD COLUMN IF NOT EXISTS height integer NOT NULL DEFAULT 0,
+    ADD COLUMN IF NOT EXISTS mime_type text NOT NULL DEFAULT '';

backend/migrations/000009_drop_photo_keys.up.sql

@@ -0,0 +1,10 @@
+-- Physical facts move to the objects table; photos keeps only membership and
+-- presentation data. size/width/height/mime_type are derived from the original
+-- object via photo_objects + objects.
+ALTER TABLE photos DROP COLUMN IF EXISTS storage_key;
+ALTER TABLE photos DROP COLUMN IF EXISTS thumb_key;
+ALTER TABLE photos DROP COLUMN IF EXISTS preview_key;
+ALTER TABLE photos DROP COLUMN IF EXISTS size;
+ALTER TABLE photos DROP COLUMN IF EXISTS width;
+ALTER TABLE photos DROP COLUMN IF EXISTS height;
+ALTER TABLE photos DROP COLUMN IF EXISTS mime_type;

backend/migrations/000010_app_settings.down.sql

@@ -0,0 +1 @@
+DROP TABLE IF EXISTS app_settings;

backend/migrations/000010_app_settings.up.sql

@@ -0,0 +1,6 @@
+CREATE TABLE IF NOT EXISTS app_settings (
+    key        text PRIMARY KEY,
+    value      text NOT NULL,
+    created_at timestamptz NOT NULL DEFAULT now(),
+    updated_at timestamptz NOT NULL DEFAULT now()
+);

backend/migrations/sqlite/000001_init.down.sql

@@ -0,0 +1,15 @@
+DROP TABLE IF EXISTS variant_jobs;
+DROP TABLE IF EXISTS photo_objects;
+DROP TABLE IF EXISTS objects;
+DROP TABLE IF EXISTS photo_tags;
+DROP TABLE IF EXISTS tags;
+DROP TABLE IF EXISTS refresh_tokens;
+DROP TABLE IF EXISTS share_links;
+DROP TABLE IF EXISTS notifications;
+DROP TABLE IF EXISTS likes;
+DROP TABLE IF EXISTS comments;
+DROP TABLE IF EXISTS invites;
+DROP TABLE IF EXISTS album_members;
+DROP TABLE IF EXISTS photos;
+DROP TABLE IF EXISTS albums;
+DROP TABLE IF EXISTS users;

backend/migrations/sqlite/000001_init.up.sql

@@ -0,0 +1,159 @@
+-- Consolidated SQLite schema equivalent to the PostgreSQL migration history.
+CREATE TABLE users (
+    id            TEXT PRIMARY KEY,
+    email         TEXT NOT NULL UNIQUE,
+    password_hash TEXT NOT NULL,
+    name          TEXT NOT NULL,
+    avatar_url    TEXT,
+    preferences   TEXT NOT NULL DEFAULT '{}',
+    created_at    TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now'))
+);
+
+CREATE TABLE albums (
+    id             TEXT PRIMARY KEY,
+    owner_id       TEXT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    title          TEXT NOT NULL,
+    description    TEXT NOT NULL DEFAULT '',
+    cover_photo_id TEXT REFERENCES photos(id) ON DELETE SET NULL,
+    created_at     TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now')),
+    updated_at     TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now'))
+);
+
+CREATE TABLE photos (
+    id                TEXT PRIMARY KEY,
+    album_id          TEXT REFERENCES albums(id) ON DELETE SET NULL,
+    uploader_id       TEXT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    original_filename TEXT NOT NULL DEFAULT '',
+    taken_at          TEXT,
+    latitude          REAL,
+    longitude         REAL,
+    caption           TEXT NOT NULL DEFAULT '',
+    exif              TEXT NOT NULL DEFAULT '{}',
+    deleted_at        TEXT,
+    created_at        TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now'))
+);
+
+CREATE INDEX photos_album_created_idx ON photos (album_id, created_at DESC, id DESC);
+CREATE INDEX photos_deleted_idx ON photos (deleted_at) WHERE deleted_at IS NOT NULL;
+
+CREATE TABLE album_members (
+    album_id   TEXT NOT NULL REFERENCES albums(id) ON DELETE CASCADE,
+    user_id    TEXT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    role       TEXT NOT NULL,
+    invited_by TEXT REFERENCES users(id) ON DELETE SET NULL,
+    joined_at  TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now')),
+    PRIMARY KEY (album_id, user_id)
+);
+
+CREATE TABLE invites (
+    id         TEXT PRIMARY KEY,
+    album_id   TEXT NOT NULL REFERENCES albums(id) ON DELETE CASCADE,
+    token      TEXT NOT NULL UNIQUE,
+    role       TEXT NOT NULL,
+    created_by TEXT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    expires_at TEXT NOT NULL,
+    max_uses   INTEGER NOT NULL DEFAULT 1,
+    uses       INTEGER NOT NULL DEFAULT 0,
+    created_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now'))
+);
+
+CREATE TABLE comments (
+    id         TEXT PRIMARY KEY,
+    photo_id   TEXT NOT NULL REFERENCES photos(id) ON DELETE CASCADE,
+    user_id    TEXT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    text       TEXT NOT NULL,
+    created_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now')),
+    updated_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now'))
+);
+
+CREATE INDEX comments_photo_idx ON comments (photo_id, created_at);
+
+CREATE TABLE likes (
+    photo_id   TEXT NOT NULL REFERENCES photos(id) ON DELETE CASCADE,
+    user_id    TEXT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    created_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now')),
+    PRIMARY KEY (photo_id, user_id)
+);
+
+CREATE TABLE notifications (
+    id           TEXT PRIMARY KEY,
+    user_id      TEXT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    type         TEXT NOT NULL,
+    payload_json TEXT NOT NULL DEFAULT '{}',
+    read_at      TEXT,
+    created_at   TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now'))
+);
+
+CREATE INDEX notifications_user_idx ON notifications (user_id, created_at DESC);
+
+CREATE TABLE share_links (
+    id         TEXT PRIMARY KEY,
+    album_id   TEXT NOT NULL REFERENCES albums(id) ON DELETE CASCADE,
+    token      TEXT NOT NULL UNIQUE,
+    created_by TEXT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    created_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now')),
+    expires_at TEXT NOT NULL,
+    revoked_at TEXT
+);
+
+CREATE TABLE refresh_tokens (
+    id         TEXT PRIMARY KEY,
+    user_id    TEXT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    token_hash TEXT NOT NULL UNIQUE,
+    expires_at TEXT NOT NULL,
+    revoked_at TEXT,
+    created_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now'))
+);
+
+CREATE INDEX refresh_tokens_user_idx ON refresh_tokens (user_id);
+
+CREATE TABLE tags (
+    id         TEXT PRIMARY KEY,
+    user_id    TEXT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    name       TEXT NOT NULL,
+    created_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now'))
+);
+
+CREATE UNIQUE INDEX tags_user_name_idx ON tags (user_id, lower(name));
+
+CREATE TABLE photo_tags (
+    photo_id TEXT NOT NULL REFERENCES photos(id) ON DELETE CASCADE,
+    tag_id   TEXT NOT NULL REFERENCES tags(id) ON DELETE CASCADE,
+    PRIMARY KEY (photo_id, tag_id)
+);
+
+CREATE INDEX photo_tags_tag_idx ON photo_tags (tag_id);
+
+CREATE TABLE objects (
+    id          TEXT PRIMARY KEY,
+    storage_key TEXT NOT NULL UNIQUE,
+    mime_type   TEXT NOT NULL DEFAULT '',
+    size        INTEGER NOT NULL DEFAULT 0,
+    width       INTEGER NOT NULL DEFAULT 0,
+    height      INTEGER NOT NULL DEFAULT 0,
+    checksum    TEXT NOT NULL DEFAULT '',
+    state       TEXT NOT NULL DEFAULT 'pending'
+        CHECK (state IN ('pending', 'ready', 'deleting')),
+    created_at  TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now'))
+);
+
+CREATE INDEX objects_state_created_idx ON objects (state, created_at);
+
+CREATE TABLE photo_objects (
+    photo_id  TEXT NOT NULL REFERENCES photos(id) ON DELETE CASCADE,
+    object_id TEXT NOT NULL REFERENCES objects(id) ON DELETE RESTRICT,
+    role      TEXT NOT NULL CHECK (role IN ('original', 'thumb', 'preview')),
+    PRIMARY KEY (photo_id, role)
+);
+
+CREATE INDEX photo_objects_object_idx ON photo_objects (object_id);
+
+CREATE TABLE variant_jobs (
+    photo_id        TEXT PRIMARY KEY REFERENCES photos(id) ON DELETE CASCADE,
+    attempts        INTEGER NOT NULL DEFAULT 0,
+    next_attempt_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now')),
+    last_error      TEXT NOT NULL DEFAULT '',
+    created_at      TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now'))
+);
+
+CREATE INDEX variant_jobs_due_idx ON variant_jobs (next_attempt_at);

backend/migrations/sqlite/000002_app_settings.down.sql

@@ -0,0 +1 @@
+DROP TABLE IF EXISTS app_settings;

backend/migrations/sqlite/000002_app_settings.up.sql

@@ -0,0 +1,6 @@
+CREATE TABLE app_settings (
+    key        TEXT PRIMARY KEY,
+    value      TEXT NOT NULL,
+    created_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now')),
+    updated_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now'))
+);

deploy/nginx-sse.conf

@@ -21,6 +21,14 @@ server {
         chunked_transfer_encoding on;
     }
 
+    location /api/objects/ {
+        proxy_pass http://shared_album;
+        proxy_http_version 1.1;
+        proxy_set_header Host $host;
+        proxy_buffering off;              # стриминг объектов без буферизации
+        proxy_cache off;
+    }
+
     location / {
         proxy_pass http://shared_album;
         proxy_http_version 1.1;

openspec/changes/archive/2026-10-10-media-object-layer/.openspec.yaml

@@ -0,0 +1,2 @@
+schema: spec-driven
+created: 2026-10-10

openspec/changes/archive/2026-10-10-media-object-layer/design.md

@@ -0,0 +1,134 @@
+# Design
+
+## Context
+
+См. `proposal.md` — Why. Текущее состояние, которое формирует подход:
+
+- `photos` хранит `storage_key`, `thumb_key`, `preview_key` (`migrations/000001_init.up.sql:45-47`),
+  а ключи строятся как `albums/{album_id}/...` (`internal/photos/service.go:72,114,115`).
+- `Clone` копирует строку фото вместе с ключами, `MoveBatch` меняет только `album_id`,
+  `PermanentDelete` удаляет объекты по счётчику ссылок `StorageKeyRefCount`
+  (`internal/photos/store.go:201`).
+- `DeletePrefix` (`internal/storage/storage.go:107`) существует, но не вызывается.
+- Очередь вариантов отсутствует: генерация запускается goroutine из HTTP-запроса
+  (`internal/photos/service.go:98`), результат не переживает рестарт.
+- Внешний API уже отдаёт `thumb_url/preview_url/original_url` и
+  `size/width/height/mime_type`; это контракт, который надо сохранить.
+- В БД только дев-данные, миграция может быть разрушительной.
+
+## Goals / Non-Goals
+
+**Goals:**
+- Убрать сущность «альбом» (и любую модель метаданных) из ключей и операций S3.
+- Сделать БД журналом истины: физический объект существует, пока на него есть ссылка.
+- Дать явный, устойчивый к сбоям сборщик мусора и самовосстанавливающуюся генерацию вариантов.
+- Сохранить внешний JSON API без изменений.
+
+**Non-Goals:**
+- Content-addressing и дедупликация одинаковых байтов между разными загрузками
+  (задел — колонка `checksum`, политика позже).
+- Мультивариантность сверх фиксированных original/thumb/preview (join-таблица это выдержит).
+- Перенос существующих данных: миграция разрушительная.
+
+## Decisions
+
+### D1. Join-таблица `photo_objects` вместо колонок-FK
+Фото ссылается на объекты через `photo_objects(photo_id, object_id, role)` с
+`PK(photo_id, role)`. Роль — свойство **связки**, не объекта: сам объект не знает,
+кто он. Альтернатива (три FK-колонки на `photos`) проще, но фиксирует ровно три
+варианта и снова смешивает представление с физикой. Выбран вариант, который
+расширяется до нескольких размеров/видео без переделки схемы.
+
+### D2. Разделение фактов: физические vs логические
+`objects` — только физические факты: `storage_key`, `mime_type`, `size`,
+`width`, `height`, `checksum`, `state`, `created_at`.
+`photos` — членство и представление: `album_id`, `uploader_id`,
+`original_filename`, `caption`, `exif`, `taken_at`, `latitude`, `longitude`,
+`deleted_at`, `created_at`.
+`size/width/height/mime_type` в API выводятся джойном к объекту-оригиналу.
+
+```sql
+objects(
+  id text pk, storage_key text unique not null, mime_type text,
+  size bigint, width int, height int, checksum text,
+  state text, created_at timestamptz)
+
+photo_objects(
+  photo_id -> photos(id) on delete cascade,
+  object_id -> objects(id) on delete restrict,
+  role text check (role in ('original','thumb','preview')),
+  primary key (photo_id, role))
+create index on photo_objects(object_id);
+
+variant_jobs(
+  photo_id -> photos(id) on delete cascade,
+  attempts int, next_attempt_at timestamptz, last_error text,
+  primary key (photo_id))
+```
+
+У `photos` удаляются `storage_key`, `thumb_key`, `preview_key`.
+
+### D3. Album-free ключи, случайный id объекта
+Ключ: `objects/{object_id}/{role}.{ext}`, где `object_id` — случайный
+(`auth.NewID()`). Роль в ключе — косметика для отладки, истина о роли — в
+`photo_objects`. Бакет, region, path-style не меняются. `DeletePrefix` удаляется.
+
+### D4. Ledger состояний и явный GC
+Объект: `pending -> ready -> deleting`. Порядок операций — **сначала строка, потом
+Put**, поэтому неубиваемый мусор «файл есть, строки нет» не возникает.
+
+```
+ Upload : INSERT objects(pending) -> S3 Put -> ready -> bind original + INSERT variant_jobs
+ Copy   : INSERT photos + bind те же objects                      -- 0 S3
+ Move   : UPDATE photos.album_id                                  -- 0 S3
+ Delete : tx DELETE photos -> cascade unbind -> mark orphaned 'deleting'
+ Worker : deleting -> re-check 0 ссылок -> S3 Delete -> DELETE row
+          pending старше T (Put не завершился) -> deleting -> S3 Delete -> DELETE row
+```
+
+Ссылочные гонки закрываются блокировками:
+- Пометить `deleting` можно только объект с нулём связок, под `SELECT ... FOR UPDATE`.
+- Перед S3 Delete воркер **перепроверяет** ноль связок под `FOR UPDATE`.
+- Привязка объекта (bind) берёт `FOR UPDATE` и отвергает `state != 'ready'`.
+
+### D5. Генерация вариантов через `variant_jobs`
+Вместо goroutine из запроса — строка задания в той же транзакции, что и загрузка.
+Воркер забирает задания через `FOR UPDATE SKIP LOCKED`, регенерирует thumb/preview,
+создаёт объекты (pending->Put->ready), вставляет связки, публикует SSE
+`photo.created`, при ошибке увеличивает `attempts` и переносит `next_attempt_at`.
+Это даёт однократное выполнение, ретраи и восстановление после рестарта.
+
+### D6. Один фоновый воркер в том же бинаре
+Петля-тикер внутри процесса (соответствует модели «один бинарь + systemd»):
+(1) доделать варианты, (2) удалить `deleting`, (3) дососить `pending`. Интервал и
+батч — конфигурируемые. Пометка объектов при удалении — синхронно в транзакции.
+
+## Risks / Trade-offs
+
+- [Двойная генерация вариантов после рестарта] → задание живёт в `variant_jobs`,
+  забирается под `SKIP LOCKED`; повторное создание объекта безопасно, лишний объект
+  соберёт GC.
+- [Удаление объекта, который вот-вот свяжут] → `FOR UPDATE` на объекте в bind и
+  повторная проверка ссылок в GC.
+- [Строка `photos` есть, объекта нет при сбое Put] → состояние `pending` + sweeper.
+- [Джойн добавляет стоимость в список фото] → один join к объекту-оригиналу; индексы
+  по `photo_objects(photo_id)` (PK) и `photo_objects(object_id)`.
+- [Ошибка в GC удалит живые байты необратимо] → удаляем только при доказанном нуле
+  ссылок; удаление идемпотентно, состояние фиксируется до S3-операции.
+- [API-совместимость] → JSON-поля сохраняются, меняется только источник значений.
+
+## Migration Plan
+
+Разрушительная (только дев-данные):
+
+1. Миграция создаёт `objects`, `photo_objects`, `variant_jobs`.
+2. Миграция удаляет `photos.storage_key`, `photos.thumb_key`, `photos.preview_key`.
+3. Существующие строки фото и объекты S3 не переносятся.
+4. Откат: down-миграция возвращает колонки и удаляет новые таблицы.
+5. `project.md` §10 приводится к новой структуре ключей.
+
+## Open Questions
+
+- Точные значения интервала воркера, размера батча и порога `T` для `pending` —
+  подбираются при реализации, на схему и контракты не влияют.
+- Формат будущего дедупа по `checksum` (политика, не схема) — вне этого change.

openspec/changes/archive/2026-10-10-media-object-layer/proposal.md

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+# Proposal
+
+## Why
+
+Слой хранения S3 сейчас знает о сущности «альбом»: ключи объектов имеют вид
+`albums/{album_id}/original/{photo_id}.{ext}` (`photos/service.go:72,114,115`).
+Это протекание модели метаданных в физический слой: перенос фото оставляет ключ в
+старом namespace, копия делит объекты под префиксом исходного альбома, а
+неиспользуемый `DeletePrefix` (`storage/storage.go:107`) создаёт латентный риск
+удаления живых объектов. Нужно развести слои: S3 хранит непрозрачные объекты, а
+сущности и их жизненный цикл живут в БД.
+
+## What Changes
+
+- Ввести таблицу `objects` — физические блобы (ключ, mime, размер, габариты,
+  checksum, состояние) и `photo_objects` — связка photo↔object с ролью
+  (`original|thumb|preview`).
+- **BREAKING**: удалить `storage_key`, `thumb_key`, `preview_key` из `photos`;
+  ключи фото выводятся через джойн к объекту-оригиналу. Миграция разрушительная
+  (в базе только дев-данные).
+- Сделать ключи S3 album-free: `objects/{id}/{role}.{ext}`, где `id` — случайный
+  идентификатор объекта.
+- Ввести явный GC через ledger-состояния объектов `pending | ready | deleting`:
+  физический объект удаляется только когда на него не осталось ни одной связки.
+- Перенести генерацию вариантов в фоновый воркер: таблица `variant_jobs`
+  (ровно-один-раз, ретраи с backoff), воркер также удаляет осиротевшие объекты и
+  досасывает зависшие `pending`. SSE `photo.created` публикует воркер.
+- Удалить `DeletePrefix` из клиента хранения — entity-namespace больше нет.
+
+## Capabilities
+
+### New Capabilities
+- `media-objects`: физическое объектное хранилище с непрозрачными ключами, журнал
+  объектов и их жизненный цикл, сборка мусора по отсутствию ссылок, привязка
+  объектов к фото по ролям.
+
+### Modified Capabilities
+- `photos`: уточняется семантика удаления (корзина не удаляет объекты хранилища) и
+  разделение объектов между фото при переносе и копировании.
+
+## Impact
+
+- Backend: `internal/photos/{service,store}.go`, `internal/storage/storage.go`,
+  `internal/albums/*` (косвенно, через ключи обложки), wiring фонового воркера,
+  `migrations/` (новая схема + удаление колонок).
+- Данные: разрушительная миграция `photos` (dev-only), новые таблицы.
+- Внешний JSON API не меняется: `thumb_url/preview_url/original_url` и
+  `size/width/height/mime_type` по-прежнему отдаются, но выводятся из объектов.
+- Документация: `project.md` §10 (структура в S3).

openspec/changes/archive/2026-10-10-media-object-layer/specs/media-objects/spec.md

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+# Spec Delta
+
+## Purpose
+
+Физическое объектное хранилище с непрозрачными ключами и журналом объектов:
+привязка объектов к фото по ролям, совместное использование объектов несколькими
+фото и сборка мусора по отсутствию ссылок.
+
+## ADDED Requirements
+
+### Requirement: Непрозрачные ключи хранилища
+Слой хранения SHALL адресоваться непрозрачными ключами объектов, не содержащими
+идентификаторов сущностей метаданных (таких как альбом или фото); сопоставление
+ключей и сущностей SHALL храниться только в слое метаданных.
+
+#### Scenario: Ключ без альбома
+- **WHEN** система сохраняет объект в хранилище
+- **THEN** ключ объекта не содержит идентификатора альбома
+
+#### Scenario: Перенос не трогает ключи
+- **WHEN** фото переносится в другой альбом
+- **THEN** ключи его объектов остаются неизменными
+
+### Requirement: Журнал объектов
+Каждый физический объект SHALL иметь ровно одну запись в слое метаданных с ключом,
+MIME-типом, размером, габаритами и состоянием; фото SHALL ссылаться на объекты по
+ролям original, thumb и preview.
+
+#### Scenario: Привязка ролей
+- **WHEN** фото загружено и обработано
+- **THEN** фото ссылается на объект-оригинал и, когда они готовы, на объекты thumb и preview
+
+#### Scenario: Оригинал без вариантов
+- **WHEN** варианты ещё не сгенерированы
+- **THEN** фото доступно с оригиналом, а thumb и preview отсутствуют
+
+### Requirement: Совместные объекты
+Несколько фото SHALL иметь возможность ссылаться на один и тот же физический
+объект; перенос и копирование SHALL изменять только ссылки и SHALL не изменять
+объекты хранилища.
+
+#### Scenario: Копирование
+- **WHEN** пользователь копирует фото в другой альбом
+- **THEN** создаётся новая запись, ссылающаяся на те же объекты, без операций с хранилищем
+
+#### Scenario: Перенос
+- **WHEN** пользователь переносит фото в другой альбом
+- **THEN** изменяется только привязка к альбому, объекты хранилища не меняются
+
+### Requirement: Сборка мусора по ссылкам
+Объект хранилища SHALL удаляться только когда на него не ссылается ни одно фото;
+удаление альбома и попадание фото в корзину SHALL сохранять объекты.
+
+#### Scenario: Последняя ссылка удалена
+- **WHEN** фото удаляется навсегда и больше ни одно фото не ссылается на его объекты
+- **THEN** объекты удаляются из хранилища
+
+#### Scenario: Остались ссылки
+- **WHEN** на объект ссылается другое фото
+- **THEN** объект сохраняется в хранилище
+
+#### Scenario: Удаление альбома
+- **WHEN** владелец удаляет альбом
+- **THEN** объекты хранилища не удаляются
+
+### Requirement: Устойчивость жизненного цикла объекта
+Объект SHALL иметь состояние жизненного цикла, и незавершённые операции SHALL
+самовосстанавливаться: неудачная загрузка не оставляет осиротевших объектов, а
+удаление объекта SHALL доводиться до конца после сбоя.
+
+#### Scenario: Сбой загрузки
+- **WHEN** запись объекта создана, но загрузка в хранилище не завершилась
+- **THEN** объект очищается без ручного вмешательства
+
+#### Scenario: Сбой удаления
+- **WHEN** удаление объекта из хранилища не удалось
+- **THEN** попытка повторяется до успешного удаления
+
+### Requirement: Генерация вариантов
+Генерация thumb и preview SHALL выполняться через надёжную очередь заданий с
+однократным выполнением и повтором при сбое; готовый результат SHALL
+транслироваться подписчикам альбома.
+
+#### Scenario: Повтор после рестарта
+- **WHEN** процесс перезапускается с незавершёнными заданиями
+- **THEN** генерация вариантов продолжается
+
+#### Scenario: Событие после генерации
+- **WHEN** варианты фото готовы
+- **THEN** подписчикам альбома публикуется событие с этим фото

openspec/changes/archive/2026-10-10-media-object-layer/specs/photos/spec.md

@@ -0,0 +1,14 @@
+# Spec Delta
+
+## MODIFIED Requirements
+
+### Requirement: Удаление фото
+Автор SHALL иметь возможность удалить своё фото; владелец и админ SHALL иметь возможность удалить любое фото. Удаление SHALL помещать фото в корзину и SHALL не удалять объекты хранилища.
+
+#### Scenario: Удаление своего фото
+- **WHEN** автор удаляет своё фото
+- **THEN** фото помещается в корзину, а объекты хранилища сохраняются
+
+#### Scenario: Удаление чужого фото участником
+- **WHEN** участник с ролью member пытается удалить чужое фото
+- **THEN** система отклоняет запрос

openspec/changes/archive/2026-10-10-media-object-layer/tasks.md

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+# Tasks
+
+## 1. Схема и миграции
+
+- [x] 1.1 Добавить миграцию, создающую `objects`, `photo_objects` (PK `photo_id,role`, индекс `object_id`) и `variant_jobs`; проверить, что `make migrate` применяется и таблицы видны в БД
+- [x] 1.2 Добавить миграцию, удаляющую `photos.storage_key`, `photos.thumb_key`, `photos.preview_key`, `photos.size`, `photos.width`, `photos.height`, `photos.mime_type`; проверить, что up и down миграции проходят в обе стороны без ошибок
+
+## 2. Слой хранения
+
+- [x] 2.1 Удалить `DeletePrefix` из `internal/storage/storage.go`; проверить `go build ./...` и отсутствие вызовов метода в коде
+- [x] 2.2 Ввести хелпер ключа объекта вида `objects/{id}/{role}.{ext}` без идентификатора альбома; покрыть юнит-тестом, что ключ не содержит album_id
+
+## 3. Метаданные объектов
+
+- [x] 3.1 Реализовать стор объектов: создание `pending`, активация `ready`, пометка `deleting`, удаление строки, выборка `pending` старше порога; покрыть тестами переходы состояний
+- [x] 3.2 Реализовать привязку `photo_objects` с блокировкой объекта `FOR UPDATE` и отказом при `state != 'ready'`; тест на повторную привязку одного объекта к двум фото
+- [x] 3.3 Реализовать запрос GC (объекты `ready` без связок) и тесты сценариев «последняя ссылка удалена» и «остались ссылки»
+
+## 4. Сервис фото
+
+- [x] 4.1 Переписать `Upload`: строка объекта `pending` → S3 Put → `ready` → привязка `original` + задание в `variant_jobs`; тест, что загрузка даёт фото с URL оригинала и ключом без альбома
+- [x] 4.2 Переписать `List`/`Get`/`attachURLs` на вывод ключей и `size/width/height/mime_type` джойном к объекту-оригиналу; тест, что JSON-поля и URL присутствуют как раньше
+- [x] 4.3 Переписать `CopyBatch`/`MoveBatch` на работу только через связки; тест, что объекты хранилища не меняются и делятся между фото
+- [x] 4.4 Переписать `PermanentDelete`: удалить связки и пометить осиротевшие объекты `deleting`; тест, что объект с нулём ссылок становится кандидатом на GC
+- [x] 4.5 Убрать обращения к удалённым колонкам во всех запросах и моделях; проверить `go build ./...` и прохождение `internal/repo` тестов
+
+## 5. Фоновый воркер
+
+- [x] 5.1 Реализовать цикл забора `variant_jobs` через `FOR UPDATE SKIP LOCKED`, генерацию thumb/preview, привязку и публикацию SSE; тест обработки задания и повтора при ошибке
+- [x] 5.2 Реализовать в воркере удаление `deleting` (с повторной проверкой нуля ссылок) и досасывание зависших `pending`; тест повторной попытки S3 Delete и очистки `pending`
+- [x] 5.3 Встроить старт/останов воркера в жизненный цикл приложения; проверить, что сервер запускается и воркер выполняет петлю (по логам/интеграционному тесту)
+
+## 6. Интеграция и документация
+
+- [x] 6.1 Перевести обложку альбома (`CoverThumbKey`) на вывод через `photo_objects`+`objects`; тест, что список альбомов отдаёт URL обложки
+- [x] 6.2 Обновить `project.md` §10 (структура в S3 и слои); проверить, что описание совпадает с реализованными ключами
+- [x] 6.3 Сквозная проверка: загрузка → генерация вариантов → копирование между альбомами (0 операций S3) → перенос → окончательное удаление → сборка объектов; проверить, что объекты удаляются только при нуле ссылок

openspec/changes/archive/2026-10-11-default-local-backends/.openspec.yaml

@@ -0,0 +1,2 @@
+schema: spec-driven
+created: 2026-10-11

openspec/changes/archive/2026-10-11-default-local-backends/proposal.md

@@ -0,0 +1,30 @@
+# Proposal
+
+## Why
+
+Слои данных были по умолчанию внешними (`postgres` и `s3`), поэтому самодостаточный
+локальный запуск без внешних сервисов требовал явной настройки. Нужно сделать локальные
+бэкенды значением по умолчанию.
+
+## What Changes
+
+- Сменить значения по умолчанию: `DB_BACKEND=sqlite` (`SQLITE_PATH=./galo.db`) и
+  `STORAGE_BACKEND=fs` (`FS_ROOT=./data`).
+- Обновить `.env.example`, `project.md`, `README.md`.
+- Поведение при явном выборе `postgres`/`s3` не меняется.
+
+## Capabilities
+
+### New Capabilities
+<!-- нет -->
+
+### Modified Capabilities
+- `metadata-backends`: значением по умолчанию становится встроенная SQLite (ранее PostgreSQL).
+- `storage-backends`: значением по умолчанию становится локальная ФС (ранее S3-совместимая).
+
+## Impact
+
+- `backend/internal/config` (значения по умолчанию) и тесты.
+- `.env.example`, `project.md`, `README.md`.
+- **BREAKING (поведение):** развёртывания без явных `DB_BACKEND`/`STORAGE_BACKEND`
+  переключатся на локальные бэкенды; для прежнего режима задайте `postgres`/`s3` явно.

openspec/changes/archive/2026-10-11-default-local-backends/specs/metadata-backends/spec.md

@@ -0,0 +1,23 @@
+# Spec Delta
+
+## MODIFIED Requirements
+
+### Requirement: Выбор бэкенда метаданных
+Система SHALL поддерживать выбор бэкенда слоя метаданных параметром конфигурации,
+при этом встроенная SQLite SHALL быть значением по умолчанию.
+
+#### Scenario: Выбор по умолчанию
+- **WHEN** бэкенд метаданных не задан в конфигурации
+- **THEN** система использует встроенную SQLite с путём по умолчанию
+
+#### Scenario: Выбор PostgreSQL
+- **WHEN** в конфигурации задан бэкенд PostgreSQL
+- **THEN** метаданные читаются и пишутся во внешнюю PostgreSQL
+
+#### Scenario: Выбор встроенной SQLite
+- **WHEN** в конфигурации задан бэкенд SQLite
+- **THEN** метаданные читаются и пишутся в локальный файл SQLite без внешней службы
+
+#### Scenario: Неполная конфигурация
+- **WHEN** конфигурация выбранного бэкенда неполна
+- **THEN** система отказывается стартовать с явной ошибкой конфигурации

openspec/changes/archive/2026-10-11-default-local-backends/specs/storage-backends/spec.md

@@ -0,0 +1,23 @@
+# Spec Delta
+
+## MODIFIED Requirements
+
+### Requirement: Выбор бэкенда хранилища
+Система SHALL поддерживать выбор бэкенда объектного хранилища параметром конфигурации,
+при этом локальная файловая система SHALL быть значением по умолчанию.
+
+#### Scenario: Выбор по умолчанию
+- **WHEN** бэкенд хранилища не задан в конфигурации
+- **THEN** система хранит и отдаёт блобы из локальной файловой системы с корнем по умолчанию
+
+#### Scenario: Выбор S3-совместимого бэкенда
+- **WHEN** в конфигурации задан S3-совместимый бэкенд
+- **THEN** система хранит и отдаёт блобы через S3-совместимое хранилище
+
+#### Scenario: Выбор локальной ФС
+- **WHEN** в конфигурации задан бэкенд локальной ФС
+- **THEN** система хранит и отдаёт блобы из каталога локальной файловой системы
+
+#### Scenario: Неполная конфигурация
+- **WHEN** конфигурация выбранного бэкенда неполна
+- **THEN** система отказывается стартовать с явной ошибкой конфигурации

openspec/changes/archive/2026-10-11-default-local-backends/tasks.md

@@ -0,0 +1,6 @@
+# Tasks
+
+## 1. Дефолты и документация
+
+- [x] 1.1 Сменить значения по умолчанию в `config` (`DB_BACKEND=sqlite`, `SQLITE_PATH=./galo.db`, `STORAGE_BACKEND=fs`, `FS_ROOT=./data`) и обновить тесты конфига; проверка — `go test ./internal/config` зелёный.
+- [x] 1.2 Обновить `.env.example`, `project.md`, `README.md`; проверка — запуск без переменных окружения стартует на SQLite+ФС и health показывает `db=ok, fs=ok`.

openspec/changes/archive/2026-10-11-local-fs-storage-backend/.openspec.yaml

@@ -0,0 +1,2 @@
+schema: spec-driven
+created: 2026-10-11

openspec/changes/archive/2026-10-11-local-fs-storage-backend/design.md

@@ -0,0 +1,107 @@
+# Design
+
+## Context
+
+См. `proposal.md` — Why. Текущее состояние, определяющее подход:
+
+- `storage.Backend` уже введён; `storage.S3` возвращает presigned URL на Garage, а
+  `storage.FS` отдаёт блобы через приложение. Presign уводит браузер напрямую в S3.
+- В проде Garage (`s3.localnet`) недоступен извне, поэтому presigned URL не работают:
+  отдача обязана идти через бэкенд для обоих бэкендов.
+- Подпись URL сейчас живёт внутри `FS` (`fs.go: sign/verify/URL`).
+- Маршрут `/api/objects/*key` и `app.serveObject` уже есть и диспетчеризуются по
+  необязательному интерфейсу `storage.ObjectServer`.
+- Ключи объектов непрозрачны (`objects/{id}/{role}{ext}`) и одинаковы для всех бэкендов.
+- Сборка `CGO_ENABLED=0`, один бинарник + systemd, перед Go стоит nginx.
+
+## Goals / Non-Goals
+
+**Goals:**
+- Единая модель доставки: любой блоб клиент получает только через бэкенд.
+- Убрать presigned URL полностью; S3 отдаёт байты через прокси бэкенда.
+- Сохранить выбор бэкенда хранилища (`s3|fs`) и непрозрачные ключи.
+- Сохранить работу анонимных share-ссылок без пользовательской сессии.
+
+**Non-Goals:**
+- Миграция существующих блобов между бэкендами.
+- Переключение бэкенда в рантайме.
+- Кэширующий CDN и раздача через внешний веб-сервер.
+- Изменение слоя метаданных (см. `sqlite-metadata-backend`).
+
+## Decisions
+
+### D1. `ServeObject` — обязательная часть `storage.Backend`
+Отдача через бэкенд нужна всем бэкендам, поэтому `ServeObject(w, r, key)` входит в
+интерфейс `Backend`, а не остаётся опциональным `ObjectServer`. Компилятор не даст
+собрать бэкенд без отдачи, а `app.serveObject` диспетчеризуется без type-assert.
+- Альтернатива: оставить `ObjectServer` опциональным — теперь это всегда реализуется,
+  опциональность только маскирует ошибку.
+
+### D2. `URL` всегда возвращает подписанный URL приложения
+`Backend.URL` больше не зависит от бэкенда в способе доставки: и `s3`, и `fs` возвращают
+`${APP_BASE_URL}/api/objects/<key>?e=<exp>&s=<sig>`. Presign-клиент AWS удаляется.
+- Альтернатива (dev): оставить presign для S3 — отвергнута по требованию «только через
+  бэкенд» и чтобы не иметь двух режимов доставки.
+
+### D3. Общий `Signer`
+HMAC-SHA256 от `key + exp` выносится в общий `Signer` (секрет `URL_SECRET` с fallback на
+`JWT_SECRET`, срок `OBJECT_URL_TTL`). Его используют и FS, и S3, и маршрут проверяет
+подпись одинаково. Внутри `FS` дублирующая подпись удаляется.
+- Альтернатива: дублировать HMAC в каждом бэкенде — риск рассинхрона проверки.
+
+### D4. Отдача S3: ranged `GetObject` и стриминг
+S3-бэкенд в `ServeObject` определяет `Range` из запроса, вызывает `GetObject` с тем же
+диапазоном (Garage отдаёт `Content-Range`) и стримит тело в ответ через `io.Copy`
+(200/206/416). HEAD обслуживается `HeadObject`. Память не растёт, размер берётся из
+`Content-Length` ответа S3.
+- Альтернатива: `http.ServeContent` требует `io.ReadSeeker`; для S3 это ranged-GET-адаптер
+  и лишний size-probe — отвергнуто ради простоты нативного passthrough.
+- `S3.Get` (в память) сохраняется только для воркера/backfill, отдачу не использует.
+
+### D5. Отдача FS: без изменений
+`FS.ServeObject` остаётся на `http.ServeContent` (Range и Content-Type бесплатно).
+Меняется лишь источник подписи — общий `Signer`.
+
+### D6. Публичный маршрут и доступ
+`/api/objects/*key` вне группы авторизации; подпись и срок — единственный контроль
+доступа, поэтому он обслуживает и авторизованных, и анонимные share-ссылки. Наружу не
+уходят ни S3-endpoint, ни AWS-подпись, ни ключ с секретом.
+
+### D7. Конфигурация
+`STORAGE_BACKEND=s3|fs` без изменений (дефолт `s3`). `FS_ROOT` — для `fs`.
+`S3_PRESIGN_TTL` переименовывается в `OBJECT_URL_TTL` (семантика: срок подписи URL).
+`S3_PUBLIC_URL` удаляется как неиспользуемая. `APP_BASE_URL` становится определяющим для
+корректности ссылок; пустое значение даёт относительный `/api/objects/...` (полагается на
+nginx того же origin).
+
+### D8. nginx для прокси-отдачи
+`location /api/objects/` обслуживается как `location /`, но с `proxy_buffering off` и
+`X-Accel-Buffering: no`, чтобы стриминг и Range не буферизовались. SSE-правило остаётся.
+
+## Risks / Trade-offs
+
+- [Все байты медиа идут через Go] → стриминг без чтения в память; `proxy_buffering off`;
+  для крупных инсталляций это принятая плата за требование «только через бэкенд».
+- [Подписанный URL действует как bearer до истечения] → срок `OBJECT_URL_TTL` (1 час),
+  отдельный `URL_SECRET` для отзыва.
+- [Range/HEAD через прокси] → passthrough `Range` в S3 и `HeadObject` для HEAD; покрыто
+  httptest-тестами (200/206/416/404).
+- [Ломающее переименование `S3_PRESIGN_TTL`] → задокументировать в `.env.example` и
+  `project.md`; при откате вернуть имя.
+- [Обход каталога через ключ FS] → нормализация пути и проверка префикса `FS_ROOT`.
+- [Смена бэкенда на существующих данных не переносит блобы] → документируем; миграция вне
+  рамок.
+
+## Migration Plan
+
+1. Вынести `Signer`, сделать `ServeObject` обязательным, `URL` — всегда app-signed.
+2. Реализовать S3 `ServeObject` (ranged `GetObject` + стриминг, HEAD).
+3. Удалить presign-путь и `S3_PUBLIC_URL`; переименовать TTL; обновить доки и nginx.
+4. Существующие развёртывания: дефолт `s3` сохраняется, но доставка теперь проксируется —
+   внешний доступ к S3 больше не нужен.
+5. Перенос блобов между бэкендами не автоматизируется.
+
+## Open Questions
+
+- Нужно ли выставлять `Cache-Control` на ответы `/api/objects/` помимо браузерного кэша
+  по уникальному URL.

openspec/changes/archive/2026-10-11-local-fs-storage-backend/proposal.md

@@ -0,0 +1,40 @@
+# Proposal
+
+## Why
+
+S3-совместимое хранилище (Garage на `s3.localnet`) в проде недоступно извне, поэтому
+отдача медиа не может идти напрямую из хранилища в браузер. Нужен слой хранения,
+который всегда отдаёт блобы через бэкенд, и локальный бэкенд для инсталляций без S3.
+
+## What Changes
+
+- Ввести интерфейс `storage.Backend`: Put/Delete/Get/Ping/EnsureBucket/Bucket, `URL`
+  (всегда подписанный URL приложения) и обязательный `ServeObject`.
+- Реализовать бэкенд локальной ФС: блобы под корневым каталогом по непрозрачным ключам
+  `objects/{id}/{role}{ext}`, защита от обхода пути, отдача через `ServeContent`.
+- Реализовать отдачу S3 через бэкенд: `ServeObject` тянет объект ranged `GetObject` из
+  Garage (внутренняя сеть) и стримит браузеру; presigned URL больше не используются.
+- Публичный маршрут `/api/objects/<key>` с HMAC-подписью, сроком, Range и Content-Type
+  обслуживает и авторизованных, и анонимные share-ссылки.
+- Ввести `STORAGE_BACKEND=s3|fs` и `FS_ROOT`; убрать `S3_PUBLIC_URL`; переименовать
+  `S3_PRESIGN_TTL` → `OBJECT_URL_TTL`; дефолт — `s3`.
+- Сделать метку хранилища в health динамической.
+- Сделать формулировки отдачи файлов нейтральными к бэкенду в спеках `photos` и `share-links`.
+
+## Capabilities
+
+### New Capabilities
+- `storage-backends`: выбор и работа объектного хранилища — S3-совместимое (Garage) и локальная ФС; блобы всегда отдаются через бэкенд по подписанному URL, хранилище клиенту не раскрывается.
+
+### Modified Capabilities
+- `photos`: получение фото и скачивание не требуют presigned URL и обслуживаются бэкендом (подписанный URL).
+- `share-links`: просмотр по ссылке отдаёт подписанный URL, обслуживаемый бэкендом.
+
+## Impact
+
+- `backend/internal/storage` (интерфейс, общий `Signer`, FS-бэкенд, S3-proxy-отдача),
+  сервисы `photos` и `albums`, `app` (маршрут отдачи, health), `cmd/*`, `config`.
+- Удаление presign-пути AWS SDK из `storage`.
+- `.env.example`, `project.md`, `deploy/nginx-sse.conf`.
+- Спеки `photos`, `share-links`, новая `storage-backends`.
+- Не затрагивает слой метаданных.

openspec/changes/archive/2026-10-11-local-fs-storage-backend/specs/photos/spec.md

@@ -0,0 +1,31 @@
+# Spec Delta
+
+## MODIFIED Requirements
+
+### Requirement: Получение фото по требованию
+Клиент SHALL иметь возможность получить актуальные данные фото с подписанным URL,
+обслуживаемым бэкендом, независимо от бэкенда хранения.
+
+#### Scenario: Выдача свежего URL
+- **WHEN** клиент запрашивает фото по id
+- **THEN** система возвращает свежий подписанный URL бэкенда (срок до 1 часа) для просмотра
+
+### Requirement: Скачивание одиночного фото
+Любой участник, включая viewer, SHALL иметь возможность скачать одиночное фото.
+
+#### Scenario: Скачивание фото
+- **WHEN** участник запрашивает скачивание фото
+- **THEN** система возвращает подписанный URL оригинала, обслуживаемый бэкендом
+
+### Requirement: Перенос и копирование фото между альбомами
+Пользователь с правом удаления в исходном альбоме и правом загрузки в целевом SHALL иметь
+возможность перенести или скопировать фото в другой альбом. Операции SHALL изменять только
+метаданные и SHALL не изменять объекты хранилища.
+
+#### Scenario: Перенос
+- **WHEN** пользователь переносит фото в другой альбом
+- **THEN** фото исчезает из исходного альбома и появляется в целевом, объекты хранилища не меняются
+
+#### Scenario: Копирование
+- **WHEN** пользователь копирует фото в другой альбом
+- **THEN** в целевом альбоме появляется новая запись, ссылающаяся на те же объекты хранилища