Ready

Readiness probe — public, unauthenticated. Returns 200 only when Postgres, both Redis DBs, and at least one Celery worker are reachable. Returns 503 with the failing subsystem names ({"status": "not_ready", "failed": [...]}). Subsystem-level *detail* (hostnames, exceptions) is logged via structlog and never returned in the body. Intended for Betterstack / external monitoring. **Do not** wire this as Railway's container healthcheck — a 30 s Redis blip would restart the API. See docs/deployment/external-monitoring.md.