Wire DCL to Instance Actors for OPC UA tag value flow

- Add TagValueUpdate/ConnectionQualityChanged handlers to InstanceActor
- InstanceActor subscribes to DCL on PreStart based on DataSourceReference
- DeploymentManagerActor creates DCL connections on deploy and passes DCL ref
- AkkaHostedService creates DCL Manager Actor for tag subscriptions
- Move CreateConnectionCommand to Commons for cross-project access
- Add ConnectionConfig to FlattenedConfiguration for deployment packaging

src/ScadaLink.Host/Actors/AkkaHostedService.cs

@@ -196,6 +196,20 @@ akka {{
         var dmLogger = _serviceProvider.GetRequiredService<ILoggerFactory>()
             .CreateLogger<DeploymentManagerActor>();
 
+        // WP-34: Create DCL Manager Actor for tag subscriptions
+        var dclFactory = _serviceProvider.GetService<ScadaLink.DataConnectionLayer.IDataConnectionFactory>();
+        var dclOptions = _serviceProvider.GetService<IOptions<ScadaLink.DataConnectionLayer.DataConnectionOptions>>()?.Value
+            ?? new ScadaLink.DataConnectionLayer.DataConnectionOptions();
+        IActorRef? dclManager = null;
+        if (dclFactory != null)
+        {
+            dclManager = _actorSystem!.ActorOf(
+                Props.Create(() => new ScadaLink.DataConnectionLayer.Actors.DataConnectionManagerActor(
+                    dclFactory, dclOptions)),
+                "dcl-manager");
+            _logger.LogInformation("Data Connection Layer manager actor created");
+        }
+
         // Create the Deployment Manager as a cluster singleton
         var singletonProps = ClusterSingletonManager.Props(
             singletonProps: Props.Create(() => new DeploymentManagerActor(
@@ -204,7 +218,8 @@ akka {{
                 sharedScriptLibrary,
                 streamManager,
                 siteRuntimeOptionsValue,
-                dmLogger)),
+                dmLogger,
+                dclManager)),
             terminationMessage: PoisonPill.Instance,
             settings: ClusterSingletonManagerSettings.Create(_actorSystem!)
                 .WithRole(siteRole)