Phase 5: Outbox DLQ, Monitoring, Consumer-Registry

- Migration 0092: DLQ columns (error_message, failed_at) + consumer_inbox RLS fix
- outbox.py: DLQ logic, replay functions, stats, consumer registry
- app/routes/outbox.py: 5 API endpoints (stats, failed, replay, replay-all, consumer-registry)
- outbox_deliveries tracking per consumer handler
- 18/18 tests passing

app/main.py

@@ -69,6 +69,7 @@ from app.routes import (
     policies,
     guest_auth,
     guests,
+    outbox,
 )
 
 
@@ -443,6 +444,7 @@ def create_app() -> FastAPI:
     app.include_router(guest_auth.router)
     app.include_router(guests.router)
     app.include_router(workspaces.router)
+    app.include_router(outbox.router)
 
     # ── Register plugin routes for all built-in plugins ──
     # Routes are registered at app creation time so OpenAPI docs are complete.