feat(WP-0004): railiance deployment & service ops

- Dockerfile (multi-stage, uv-based, slim runtime)
- .dockerignore
- docker-compose.railiance.yml (Temporal + NATS + PG, no Elasticsearch)
- GET /health endpoint (db + temporal probes, 200/503)
- .env.example (complete env var reference)
- Makefile: migrate, sync-all, dev-up/down, railiance-up/down,
  start-worker, start-api, start-event-router, help targets;
  extracted sync-event-types Python to scripts/sync_event_types.py
- SIGTERM graceful shutdown in worker.py and event_router.py
- docs/runbook.md: Railiance deployment section

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

src/activity_core/event_router.py

@@ -23,6 +23,7 @@ from __future__ import annotations
 import asyncio
 import logging
 import os
+import signal
 import uuid
 from datetime import datetime, timezone
 from typing import Any
@@ -202,12 +203,19 @@ class EventRouter:
             _CONSUMER_NAME,
         )
 
+        loop = asyncio.get_running_loop()
+        stop = asyncio.Event()
+        loop.add_signal_handler(signal.SIGTERM, stop.set)
+        loop.add_signal_handler(signal.SIGINT, stop.set)
+
         try:
-            await asyncio.Future()  # run until cancelled
+            await stop.wait()
+            logger.info("Shutdown signal received — draining event router")
         finally:
             await sub.unsubscribe()
             await self._nc.drain()
             await engine.dispose()
+        logger.info("Event router stopped cleanly")
 
 
 async def main() -> None: