This commit introduces a new validation step to ensure data integrity
during file uploads.
- The API's returned file name (new.File.Name) is now verified
against the requested file name (leaf) immediately after
the initial upload ticket is created.
- If a mismatch is detected, the upload process is aborted with an error,
and the defer cleanup logic is triggered to delete any partially created file.
- This addresses an unexpected API behavior where numbered suffixes
might be appended to filenames even without conflicts.
- This change prevents corrupted or misnamed files from being uploaded
without client-side awareness.
ca6631746a