feat: rename service to galo, add halo branding and release build

- rename Go module, binary, systemd unit, PG_DATABASE default, frontend package and docs from shared-album to galo
- add theme-aware halo emblem and favicon (new ui-branding capability)
- add make build-release (versioned, stripped, static binary) and run the binary from the repo root

backend/internal/social/handlers.go

@@ -5,8 +5,8 @@ import (
 
 	"github.com/gin-gonic/gin"
 
-	"shared-album/internal/auth"
-	"shared-album/internal/httpx"
+	"galo/internal/auth"
+	"galo/internal/httpx"
 )
 
 type Handler struct {

backend/internal/social/repository.go

@@ -3,7 +3,7 @@ package social
 import (
 	"context"
 
-	"shared-album/internal/models"
+	"galo/internal/models"
 )
 
 // Repository is the persistence contract for the social domain.

backend/internal/social/service.go

@@ -5,11 +5,11 @@ import (
 	"errors"
 	"strings"
 
-	"shared-album/internal/auth"
-	"shared-album/internal/httpx"
-	"shared-album/internal/models"
-	"shared-album/internal/roles"
-	"shared-album/internal/sse"
+	"galo/internal/auth"
+	"galo/internal/httpx"
+	"galo/internal/models"
+	"galo/internal/roles"
+	"galo/internal/sse"
 )
 
 type AlbumAccess interface {

backend/internal/social/sqlite_store.go

@@ -5,8 +5,8 @@ import (
 	"database/sql"
 	"errors"
 
-	"shared-album/internal/models"
-	"shared-album/internal/sqliteutil"
+	"galo/internal/models"
+	"galo/internal/sqliteutil"
 )
 
 // SQLiteStore is the SQLite implementation of Repository.

backend/internal/social/store.go

@@ -7,7 +7,7 @@ import (
 	"github.com/jackc/pgx/v5"
 	"github.com/jackc/pgx/v5/pgxpool"
 
-	"shared-album/internal/models"
+	"galo/internal/models"
 )
 
 var ErrNotFound = errors.New("not found")