feat(WP-0002): complete Triggers & Ops workstream

Delivers all 12 tasks (T22–T33): Temporal Schedule manager + startup
sync, NATS JetStream event router, FastAPI CRUD + manual trigger,
Prometheus metrics wiring, custom search-attribute tagging, and
operational runbook. Marks workplan status as done.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker-compose.dev.yml

@@ -124,6 +124,22 @@ services:
     stdin_open: true
     tty: true
 
+  # ── NATS JetStream (event broker for EventRouter) ────────────────────────────
+  nats:
+    container_name: actcore-nats
+    image: docker.io/nats:2.10-alpine
+    command: ["-js", "-m", "8222"]
+    networks:
+      - activity-net
+    ports:
+      - "4222:4222"   # client connections
+      - "8222:8222"   # monitoring / HTTP
+    healthcheck:
+      test: ["CMD-SHELL", "wget -qO- http://localhost:8222/healthz || exit 1"]
+      interval: 5s
+      timeout: 5s
+      retries: 10
+
   # ── App database (activity-core application data) ─────────────────────────────
   app-db:
     container_name: actcore-app-db