A natural fire whose instant equals the skip or the handled-occurrence watermark is ignored, so a dismissal racing a reschedule cannot ring. Dismissing a repeating alarm persists its resolution before arming the skip, so an unspent old skip cannot absorb it. The deferred notice sync runs even if starting the ring throws, the swipe record is one synchronised read-modify-write, and it stays out of backups.
Fixes#16