feat: implement shared-album multi-user photo album

Backend (Go/Gin/pgx): env config, pgx pool with retries, Garage S3 client
(path-style, region garage), embedded golang-migrate migrations, JWT auth with
refresh rotation, albums CRUD, members/roles/invites with no-escalation matrix,
photo upload + async imaging/goexif WebP variants, cursor pagination, presigned
URLs, likes/comments, SSE hub (album + personal), notifications, share links.

Frontend (SvelteKit 2 + Svelte 5 + Tailwind v4): API wrapper with 401 refresh,
auth store, all screens, Uploader/PhotoGrid/Lightbox/Comments, SSE client with
reconnect + REST catch-up, three themes + system via data-theme.

Deploy without Docker: Makefile builds the frontend into backend/static and
embeds it (go:embed) into a single statically linked binary; systemd unit and
nginx SSE example included.

Use gen2brain/webp (-tags nodynamic) instead of cgo kolesa-team/go-webp to keep
CGO_ENABLED=0 static builds; design.md/proposal.md updated accordingly.

frontend/tailwind.config.ts

@@ -0,0 +1,28 @@
+import type { Config } from 'tailwindcss';
+
+export default {
+	content: ['./src/**/*.{html,js,svelte,ts}'],
+	theme: {
+		extend: {
+			colors: {
+				bg: {
+					DEFAULT: 'hsl(var(--bg) / <alpha-value>)',
+					elevated: 'hsl(var(--bg-elevated) / <alpha-value>)',
+					muted: 'hsl(var(--bg-muted) / <alpha-value>)'
+				},
+				border: 'hsl(var(--border) / <alpha-value>)',
+				text: {
+					DEFAULT: 'hsl(var(--text) / <alpha-value>)',
+					muted: 'hsl(var(--text-muted) / <alpha-value>)',
+					subtle: 'hsl(var(--text-subtle) / <alpha-value>)'
+				},
+				primary: {
+					DEFAULT: 'hsl(var(--primary) / <alpha-value>)',
+					fg: 'hsl(var(--primary-fg) / <alpha-value>)'
+				},
+				danger: 'hsl(var(--danger) / <alpha-value>)',
+				success: 'hsl(var(--success) / <alpha-value>)'
+			}
+		}
+	}
+} satisfies Config;