Move library collections as a group and map v2 identity refs.

Collapsed collection actions now move, rename, delete, and rerun every part so chains stay together. Identity mode follows the v2u3 Ref2VA picture wiring.

Co-authored-by: Cursor <cursoragent@cursor.com>

server/api/library/index.get.ts

@@ -5,6 +5,7 @@ export default defineEventHandler(async (event) => {
     const folderId = library.folders.find(folder => folder.unlocked)?.id
     if (folderId) await importMissingComfyVideos(owner, folderId)
     await ensureClipThumbnails(owner)
+    await sweepOwnerExtensionStills(owner)
   } catch {
     return publicLibrary(event)
   }