The file input's `onChange` reset `state` to `IDLE` and left `altText`
untouched. On success that is harmless -- the dialog unmounts. But
REJECTED, QUARANTINED and TRANSPORT_FAILED all leave it mounted with the
file input re-enabled, and that is precisely the retry path: upload
`db-schema.png` described as "DB 스키마", have it quarantined, pick
`sequence.png`, upload -- and `sequence.png` shipped described as
"DB 스키마", passing EVIDENCE_ALT_REQUIRED and publishing with a caption
about a different image.
Cleared on every file selection rather than only after a failure: alt
text describes one image, and "which file is this describing" has one
honest answer per selection. `submit()`'s existing ALT_REQUIRED refusal
turns the emptied field into a stop rather than a silent omission.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
