fix: handle already-serialized mount dicts in profile update

When FastAPI parses the request body and model_dump() is called,
nested MountItem models are already serialized to plain dicts.
The update handler was unconditionally calling model_dump() again,
causing AttributeError on dict objects.

Fix: Check if mount items are already dicts before calling model_dump().

Fixes: 422 error when updating profiles with mounts.

apps/api/src/api/config_profiles.py

@@ -429,7 +429,7 @@ async def update_config_profile(
         if field_name in ("project_id", "tool_type_id"):
             value = uuid.UUID(value) if value else None
         elif field_name == "mounts" and value is not None:
-            value = [m.model_dump() for m in value]
+            value = [m.model_dump() if not isinstance(m, dict) else m for m in value]
         setattr(profile, field_name, value)
 
     await session.commit()