feat: photo multiselect, move/copy, trash and compact chrome

- backend: soft delete + trash (photos.deleted_at, migration 000005), GET /trash, restore, permanent delete with storage-key refcount (S3 objects removed only when no other album references them); batch endpoints photo-batch/{delete,move,copy} - metadata only, copies clone rows sharing storage keys
- frontend: Ctrl/Shift multiselect; right-panel 'Действия' as icon text rows (Открыть (просмотр), Переместить, Копировать, Удалить); drag selected photos onto rail album -> TransferDialog; /trash route; trash entry as last item in the left rail; empty right panel hidden on overview
- frontend: compact top bars (app header and viewer), compact theme switcher
- openspec: sync lightroom-workspace-ui artifacts (photos/ui-workspace specs, design #20-24, tasks 9.11-9.17)

backend/migrations/000005_photo_trash.down.sql

@@ -0,0 +1,2 @@
+DROP INDEX IF EXISTS photos_deleted_idx;
+ALTER TABLE photos DROP COLUMN IF EXISTS deleted_at;

backend/migrations/000005_photo_trash.up.sql

@@ -0,0 +1,2 @@
+ALTER TABLE photos ADD COLUMN IF NOT EXISTS deleted_at timestamptz;
+CREATE INDEX IF NOT EXISTS photos_deleted_idx ON photos (deleted_at) WHERE deleted_at IS NOT NULL;