All three workers now share a run_health_heartbeat helper in
decnet.bus.publish. Each publishes system.<worker>.health on a 30s tick
with {worker, ts} plus optional per-worker extras. Subscribers can
watch system.*.health to see every DECNET worker on a host at once.
- agent: heartbeat runs inside the FastAPI lifespan alongside the
existing master-facing heartbeat; bus-disabled path is a no-op.
- forwarder: heartbeat task spawned at run_forwarder entry, cancelled
in the finally block so a crashed master loop never leaks the task.
- updater: new FastAPI lifespan hosts the heartbeat.
Heartbeat helper swallows extra() failures and is cancellation-safe so
lifespan teardown never hangs on it.
anti
5c0631e12c