- IMAP CONDSTORE (RFC 7162): skip sync when HIGHESTMODSEQ is unchanged;
refresh only changed flags via CHANGEDSINCE on incremental sync
- JMAP blob expiry: re-fetch email bodies older than 7 days (schema v8→v9
adds nullable cachedAt column to email_bodies)
- Offline compose queue: expose stuck pending_changes rows via
observeFailedMutations / retryMutation / discardMutation; surface them
in a FailedMutationBanner on the mailbox list screen
- Unit tests for all three features (236 passing)
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
