- Add map_vfs_error() to map VfsError to FsError properly - NotFound → NotFound, PermissionDenied → Forbidden, etc. - Update create_dir/remove_dir/remove_file/rename/set_atime/set_mtime/get_quota - Add executable() method to VfsDavMetaData (mode & 0o111) Tests: 288 passed, 0 failed