fix(immich): remove album photos on unlink

When unlinking an Immich album, photos synced from that album are now
deleted. A new `album_link_id` FK column on `trip_photos` tracks the
source album link at sync time; `deleteAlbumLink` deletes matching
photos before removing the link. Individually-added photos are
unaffected. The client now refreshes the photo grid after unlinking.

Adds integration tests IMMICH-020 through IMMICH-024.

Closes #398

server/tests/helpers/test-db.ts

@@ -36,6 +36,8 @@ const RESET_TABLES = [
   'packing_items',
   'budget_item_members',
   'budget_items',
+  'trip_photos',
+  'trip_album_links',
   'trip_files',
   'share_tokens',
   'photos',