feat(runtime): F11 — HistorianAdapterActor wired to IAlarmHistorianSink

Reshapes the placeholder buffered-counter actor into a thin fire-and-forget
bridge over the existing IAlarmHistorianSink contract. Default sink is
NullAlarmHistorianSink; production deployments override the DI binding to
SqliteStoreAndForwardSink wrapping WonderwareHistorianClient (the v1
components in src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Historian.Wonderware*
are reused verbatim — actor is just a mailbox-friendly entry point).

- HistorianAdapterActor.Props(IAlarmHistorianSink?) — null defaults to NullAlarmHistorianSink
- Receive<AlarmHistorianEvent>: fire-and-forget sink.EnqueueAsync
- Receive<GetStatus>: returns sink.GetStatus() (queue depth + drain state)
- ServiceCollectionExtensions.AddOtOpcUaRuntime registers the default sink
- WithOtOpcUaRuntimeActors spawns the actor + registers HistorianAdapterActorKey
- Program.cs calls AddOtOpcUaRuntime when hasDriver

Tests: 2 new (forward-to-sink + GetStatus). Runtime suite 17 → 18.

tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/ServiceCollectionExtensionsTests.cs

@@ -46,11 +46,14 @@ public sealed class ServiceCollectionExtensionsTests
         {
             var driverHost = host.Services.GetRequiredService<IRequiredActor<DriverHostActorKey>>();
             var dbHealth = host.Services.GetRequiredService<IRequiredActor<DbHealthProbeActorKey>>();
+            var historian = host.Services.GetRequiredService<IRequiredActor<HistorianAdapterActorKey>>();
 
             driverHost.ActorRef.ShouldNotBeNull();
             dbHealth.ActorRef.ShouldNotBeNull();
+            historian.ActorRef.ShouldNotBeNull();
             driverHost.ActorRef.Path.Name.ShouldBe(ServiceCollectionExtensions.DriverHostActorName);
             dbHealth.ActorRef.Path.Name.ShouldBe(ServiceCollectionExtensions.DbHealthProbeActorName);
+            historian.ActorRef.Path.Name.ShouldBe(ServiceCollectionExtensions.HistorianAdapterActorName);
         }
         finally
         {