feat: TR-069 Exchange Viewer - structured MongoDB storage with SSE streaming and sequence diagram UI
- MongoDB storage: cwmp_exchanges collection with indexes (deviceId+timestamp, deviceId+sequenceNumber unique, TTL 24h)
- ExchangeStoreService: CWMP method extraction, per-device queue for ordering, retry logic, message cap (5000/device)
- Exchange API: GET/DELETE/SSE stream endpoints with Last-Event-ID reconnection
- CwmpLoggerMiddleware: dual-write (MongoDB + legacy files) with fire-and-forget
- Frontend: SequenceViewer (CPE↔ACS lifelines, arrows, auto-scroll, virtual scroll) + InspectorPanel (formatted XML, copy, syntax highlighting)
- Tr069Trace page: integrated new viewer with col-6/col-6 layout
- DeviceDetail page: collapsible exchange section when device is traced
- 14 property-based tests, 40+ unit tests, 5 integration tests
- Health check includes index verification
- Config: feature flags, SSE timeouts, retry policy
Kevin L'Hereec
0c83a4ccb2