Lucas Berger
aa7c4c37d4
feat(03-06): implement SyncStateToast with polled sync-status feedback (D-05/D-06/D-08/D-09)
- SyncStateToast: pending/done/failed/dead states per UI-SPEC
- refetchInterval 3000ms while pending; disabled on terminal status
- done + conflict (412) invalidate ['events'] cache (D-06/D-08)
- done auto-dismisses after 2s; failed/dead persist with dismiss button
- role=status (pending/done) and role=alert (failed/dead) for a11y
- Mounted in CalendarShell (both phone + tablet/desktop layouts)
- EventForm.onSuccess: setLastSyncedUid(uid) instead of invalidateQueries