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>

Dockerfile

@@ -0,0 +1,19 @@
+# Stage 1 — install Python deps
+FROM python:3.12-slim AS builder
+RUN pip install uv --no-cache-dir
+WORKDIR /app
+COPY pyproject.toml uv.lock ./
+COPY src/ ./src/
+RUN uv sync --no-dev --frozen
+
+# Stage 2 — runtime image
+FROM python:3.12-slim AS runtime
+WORKDIR /app
+COPY --from=builder /app/.venv /app/.venv
+COPY --from=builder /app/src /app/src
+COPY activity-definitions/ ./activity-definitions/
+COPY event-types/ ./event-types/
+COPY tasks/ ./tasks/
+ENV PATH="/app/.venv/bin:$PATH"
+ENV PYTHONPATH="/app/src"
+CMD ["python", "-m", "activity_core.worker"]