The navigation pane now matches the document structure from database, but breadcrumbs bar became broken, not yet fixed.
Added check to folder creation so that subfolders cannot be created in parent folders that don't exist.
Backend works when trying to use Postman to request the API endpoint. File upload in the frontend also works since the data is parsed properly as multi-part form data. The issue is the frontend seems to cannot directly send request to backend and is outright rejected.
