corrige nombre de playlists curadas: elimina fields= en llamada a API

El parámetro fields="name,description,images" causaba error en playlists
curadas de Spotify (ej. "This Is ..."), haciendo que el nombre cayera
al fallback con el spotify_id.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/routers/admin.py

@@ -45,9 +45,9 @@ def _extract_spotify_item(value: str) -> tuple[str, str] | None:
 
 def _fetch_metadata(sp, spotify_id: str, spotify_type: str) -> dict:
     if spotify_type == "playlist":
-        data = sp.playlist(spotify_id, fields="name,description,images")
+        data = sp.playlist(spotify_id)
         return {
-            "name": data["name"],
+            "name": data.get("name") or spotify_id,
             "description": data.get("description") or "",
             "image_url": data["images"][0]["url"] if data.get("images") else "",
         }