feat: context menus, unified photo panel, tags, album trash and counters

- backend: deleting an album moves its photos to the trash without losing files (photos.album_id nullable, FK ON DELETE SET NULL, migration 000006; dropped S3 prefix delete); restore accepts an album target (album_required when the album is gone); user-scoped tags (000007) with GET /tags, POST/DELETE /photos/:id/tags, tags included in photo responses; GET /trash/count
- frontend: right-click context menus for photos (grid + viewer) and albums (rail + overview); single shared PhotoPanel reused in viewer and gallery selection (not a copy); viewer download/delete moved to the panel 'Действия'; transparent compact viewer top bar; trash entry as last rail item with per-album photo counts and trash count; album rename/delete dialogs
- openspec: sync lightroom-workspace-ui artifacts (specs photos/ui-workspace, design #24-30, tasks 9.17-9.24)

frontend/src/lib/components/PhotoGrid.svelte

@@ -9,9 +9,11 @@
 		onSelect?: (index: number, event: MouseEvent) => void;
 		onOpen?: (index: number) => void;
 		onDragStart?: (index: number, event: DragEvent) => void;
+		onContextMenu?: (index: number, event: MouseEvent) => void;
 	}
 
-	let { photos, selectedIds = [], onSelect, onOpen, onDragStart }: Props = $props();
+	let { photos, selectedIds = [], onSelect, onOpen, onDragStart, onContextMenu }: Props =
+		$props();
 
 	const isSelected = (id: string) => selectedIds.includes(id);
 </script>
@@ -37,6 +39,7 @@
 					onclick={(e) => onSelect?.(i, e)}
 					ondblclick={() => onOpen?.(i)}
 					ondragstart={(e) => onDragStart?.(i, e)}
+					oncontextmenu={(e) => onContextMenu?.(i, e)}
 				>
 					{#if photo.thumb_url}
 						<img