feat: Immich album linking with auto-sync (#206)

- Link Immich albums to trips — photos sync automatically
- Album picker shows all user's Immich albums
- Linked albums displayed as chips with sync/unlink buttons
- Auto-sync on link: fetches all album photos and adds to trip
- Manual re-sync button for each linked album
- DB migration: trip_album_links table

fix: shared Immich photos visible to other trip members

- Thumbnail/original proxy now uses photo owner's Immich credentials
  when userId query param is provided, fixing 404 for shared photos
- i18n: album keys for all 12 languages

server/src/db/migrations.ts

@@ -439,6 +439,22 @@ function runMigrations(db: Database.Database): void {
     () => {
       try { db.exec('ALTER TABLE budget_items ADD COLUMN expense_date TEXT DEFAULT NULL'); } catch {}
     },
+    () => {
+      db.exec(`
+        CREATE TABLE IF NOT EXISTS trip_album_links (
+          id INTEGER PRIMARY KEY AUTOINCREMENT,
+          trip_id INTEGER NOT NULL REFERENCES trips(id) ON DELETE CASCADE,
+          user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+          immich_album_id TEXT NOT NULL,
+          album_name TEXT NOT NULL DEFAULT '',
+          sync_enabled INTEGER NOT NULL DEFAULT 1,
+          last_synced_at DATETIME,
+          created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+          UNIQUE(trip_id, user_id, immich_album_id)
+        );
+        CREATE INDEX IF NOT EXISTS idx_trip_album_links_trip ON trip_album_links(trip_id);
+      `);
+    },
   ];
 
   if (currentVersion < migrations.length) {