- Preserve multipart chunk errors to prevent nil upload results and downstream panics.
- Cancel and wait for multipart workers on failure, and attempt to abort OSS uploads with the current security token.
- Map WebDAV upload errors to appropriate HTTP status codes: 403 for permission failures, 405 for unsupported uploads, and 500 for other backend failures.
Fixes#3201
Co-authored-by: LunelleEverdawn <lunelle+suyunmeng@oplist.org>