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.

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/ZB.MOM.WW.OtOpcUa.Runtime.csproj

@@ -24,6 +24,7 @@
             the reflective-load design.
         -->
         <ProjectReference Include="..\..\Core\ZB.MOM.WW.OtOpcUa.Core.Abstractions\ZB.MOM.WW.OtOpcUa.Core.Abstractions.csproj"/>
+        <ProjectReference Include="..\..\Core\ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian\ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.csproj"/>
     </ItemGroup>
 
     <ItemGroup>