After receiving the initial snapshot via ClusterClient, the bridge actor
now opens a gRPC server-streaming subscription via SiteStreamGrpcClient
for ongoing AttributeValueChanged/AlarmStateChanged events. Adds NodeA/
NodeB failover with max 3 retries, retry count reset on successful event,
and IWithTimers-based reconnect scheduling.
- DebugStreamBridgeActor: gRPC stream after snapshot, reconnect state machine
- DebugStreamService: inject SiteStreamGrpcClientFactory, resolve gRPC addresses
- ServiceCollectionExtensions: register SiteStreamGrpcClientFactory singleton
- SiteStreamGrpcClient: make SubscribeAsync/Unsubscribe virtual for testability
- SiteStreamGrpcClientFactory: make GetOrCreate virtual for testability
- New test suite: DebugStreamBridgeActorTests (8 tests)
The debug view polled every 2s by re-subscribing for full snapshots. Now a
persistent DebugStreamBridgeActor on central subscribes once and receives
incremental Akka stream events from the site, forwarding them to the Blazor
component via callbacks and to the CLI via a new SignalR hub at
/hubs/debug-stream. Adds `debug stream` CLI command with auto-reconnect.
