internal/notify: a Novu-compatible POST /v1/events/trigger client (quarry triggers, notify owns delivery). chat.post parses @mentions and fires quarry-mention per handle; wiki/ticket write ops fire quarry-activity to a repo:<name> topic. All best-effort — a notify outage never fails the user action — with idempotency keys so replays dedup. --notify enables it (disabled by default). Verified live: mention and activity triggers POSTed with the right Novu shape. check-in: 37f62c9a82 user: dmestas tags: trunk