"Replay"
- 3.7 Event Contract 與 Replay Boundary 說明 event schema、idempotency key、replay window 與補償如何先於 broker 選型。
- 3.8 Queue Consumer Retry 與 Replay Handoff(實作示範) 以 order_created consumer 示範 queue 路徑如何交付 idempotency evidence、DLQ handling、replay runbook 與 incident decision log。