feat(siteeventlog): emit alarm-category events on alarm transitions (M1.5)

AlarmActor (computed) and NativeAlarmActor (native mirror) now fire-and-forget
an 'alarm' site operational event on every state transition:
- raise/activate: Error (priority/severity >= 700) or Warning
- clear/return-to-normal, ack, inter-band transition: Info

Both actors take a new optional IServiceProvider? ctor param (default null so
existing direct-construction tests still compile); InstanceActor passes its
_serviceProvider at the two Props.Create sites. Resolution is optional and the
LogEventAsync call is fire-and-forget, so a logging failure never affects alarm
evaluation. Rehydration replays are not re-logged.

Adds a capturing FakeSiteEventLogger test helper + SingleServiceProvider.

src/ZB.MOM.WW.ScadaBridge.SiteRuntime/Actors/InstanceActor.cs

@@ -763,7 +763,8 @@ public class InstanceActor : ReceiveActor
                 _logger,
                 triggerExpression,
                 attributeSnapshot,
-                _healthCollector));
+                _healthCollector,
+                _serviceProvider));
 
             var actorRef = Context.ActorOf(props, $"alarm-{alarm.CanonicalName}");
             _alarmActors[alarm.CanonicalName] = actorRef;
@@ -793,7 +794,8 @@ public class InstanceActor : ReceiveActor
                 _storage,
                 _options,
                 _logger,
-                nativeKind));
+                nativeKind,
+                _serviceProvider));
 
             var actorRef = Context.ActorOf(props, $"native-alarm-{nativeSource.CanonicalName}");
             _nativeAlarmActors[nativeSource.CanonicalName] = actorRef;