After a partial upload failure (manga created, a chapter failed), re-submitting
re-ran createManga and spawned a duplicate manga. Track the created manga id:
a retry skips creation, re-sends only the not-yet-done chapters, disables the
now-saved title, relabels the button "Retry failed chapters", and shows a note.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
