- IDriverHealthPublisher in Core.Abstractions + NullDriverHealthPublisher
no-op for tests/dev-stub paths.
- AkkaDriverHealthPublisher in Runtime forwards to the cluster-wide
`driver-health` DPS topic.
- DriverInstanceActor instrumented to publish snapshots on every
observable state change + a periodic 30s heartbeat so the AdminUI
snapshot store warms up for newly-joined SignalR clients.
- Sliding 5-minute Faulted-count tracked per actor via Queue<DateTime>.
- DriverHostActor.SpawnChild threads clusterId (_localNode.Value) and
the health publisher down to every DriverInstanceActor child.
- ServiceCollectionExtensions.AddOtOpcUaRuntime registers
AkkaDriverHealthPublisher as IDriverHealthPublisher singleton.
Joseph Doherty