- Check notUpdated/notDestroyed per-item errors in Email/set; throw
JmapSetItemException for permanent failures (notFound, forbidden) so
they are discarded immediately rather than retried
- Add _maxChangeAttempts=5 constant; _recordChangeError() evicts the
pending-change row when attempts reach the limit, preventing unbounded
queue growth from transient errors
- Both IMAP and JMAP flush paths now use _recordChangeError() consistently
- Document server-wins conflict-resolution policy in DB-SYNC.md
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>