feat(debugview): DV-1 native-binding linkage on AlarmStateChanged contract chain

Add two additive init-only fields to AlarmStateChanged so the Debug View can
nest live native conditions under their configured source-binding node:
  - NativeSourceCanonicalName (binding canonical name, e.g. "Motor1.MotorAlarms")
  - IsConfiguredPlaceholder (quiet-binding placeholder flag; default false)

Flow on BOTH cross-process paths:
  - Live: proto AlarmStateUpdate fields 22/23 -> StreamRelayActor packs ->
    SiteStreamGrpcClient unpacks (regenerated SiteStreamGrpc/Sitestream.cs).
  - Snapshot (Newtonsoft): record defaults carry through; no special handling.

NativeAlarmActor.Emit now stamps NativeSourceCanonicalName = _source.CanonicalName.
Additive-only: no existing positional constructor or wire frame changed.

Tests: StreamRelayActorTests round-trips both fields pack->unpack;
NativeAlarmActorTests asserts the emitted event carries the binding canonical name.

src/ZB.MOM.WW.ScadaBridge.Communication/Protos/sitestream.proto

@@ -84,6 +84,8 @@ message AlarmStateUpdate {
   google.protobuf.Timestamp original_raise_time = 19;  // null when unknown
   string current_value = 20;
   string limit_value = 21;
+  string native_source_canonical_name = 22;  // native binding canonical name; empty for computed
+  bool is_configured_placeholder = 23;        // true for a quiet-binding placeholder row
 }
 
 // Audit Log (#23) telemetry: single lifecycle event ferried from a site SQLite