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/internal/models/models.go

@@ -78,6 +78,8 @@ type Photo struct {
 	Longitude        *float64   `json:"longitude,omitempty"`
 	Caption          string         `json:"caption"`
 	EXIF             map[string]any `json:"exif,omitempty"`
+	DeletedAt        *time.Time     `json:"deleted_at,omitempty"`
+	AlbumTitle       string         `json:"album_title,omitempty"`
 	CreatedAt        time.Time      `json:"created_at"`
 	Uploader         PublicUser `json:"uploader"`
 	LikesCount       int        `json:"likes_count"`