Adds a NATS JetStream consumer to ml/serving so the feature pipeline
can react to events without the API triggering every read.
- nats_consumer.py: durable push consumers for signals.> and feedback.>
streams; acks on success, naks for redeliver, up to NATS_MAX_DELIVER
attempts; per-consumer health state (last_msg_ts, processed, errors)
- main.py: FastAPI lifespan wires start/stop; /health exposes nats state
- requirements.txt: adds nats-py>=2.9.0
- Dockerfile.ml: copy all *.py from ml/serving (was missing prompts.py)
Handled subjects:
signals.task.synced → writes per-user sync metadata to STATE_DIR
signals.tip.feedback → logged for observability (reward via HTTP path)
Config: NATS_URL (empty = disabled), NATS_DURABLE_PREFIX, NATS_MAX_DELIVER
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>