Resume Itinerary

Resume a paused route.

last_fired_signature is deliberately preserved, which is what an ordinary alert does: the per-site path filters every change against existing active/seen AlertMatch rows for the same (alert_id, site_id) before it dispatches, so a resumed alert can never re-announce something the user has already looked at — and its resume additionally skips one whole match cycle (_resumed_alert_ids) to avoid a stale-state burst.

Clearing the signature here made routes the only surface that re-announces on resume, and the openings it named kept their seen_at — so a toggle produced a push describing start days the card had been rendering as already-read for days. A notification with nothing behind it is worse than silence: it teaches the user to ignore the channel.

Preserving it keeps the half that mattered. The matcher is level-triggered, so if the bookable set CHANGED while the route was paused its signature differs and the next sweep fires normally — the user IS told what is open now. Only the exact set they were last notified about stays quiet.

Edits that change the QUESTION (window, party_size, tent_pads) still re-baseline in update_itinerary: a different question deserves a fresh answer, exactly as editing an alert's criteria does.