When a user has no home folder (e.g., legacy users or failed folder
creation during registration), the frontend would get an empty list
from GET /api/folders, leaving userHomeFolderId undefined. This caused
uploads to fail or go to the wrong location.
Now list_folders_for_owner() automatically creates a home folder when:
- Listing root folders (parent_id is None)
- The result is empty
This self-healing approach fixes the issue at the source, ensuring
the frontend always gets a valid userHomeFolderId.
George Wu
f3f5c40b6b