feat(deployment-manager): resolve DeploymentManager-006 — query site deployment state before redeploy and reconcile

Adds DeploymentStateQuery request/response contracts (Commons), a site-side
handler (SiteRuntime), a CommunicationService query method (Communication), and
reconciliation in DeploymentService: when a prior record is InProgress or
Failed-on-timeout, query the site; if it already holds the target revision hash
mark the record Success without re-sending; on query failure fall through to a
normal deploy (site-side stale-rejection is the safety net).

tests/ScadaLink.Communication.Tests/SiteCommunicationActorTests.cs

@@ -51,6 +51,22 @@ public class SiteCommunicationActorTests : TestKit
         dmProbe.ExpectMsg<DeleteInstanceCommand>();
     }
 
+    [Fact]
+    public void DeploymentStateQuery_ForwardedToDeploymentManager()
+    {
+        // DeploymentManager-006: the site-before-redeploy query travels over the
+        // ClusterClient command/control transport and is routed to the local
+        // Deployment Manager, which owns the deployed-config store.
+        var dmProbe = CreateTestProbe();
+        var siteActor = Sys.ActorOf(Props.Create(() =>
+            new SiteCommunicationActor("site1", _options, dmProbe.Ref)));
+
+        var request = new DeploymentStateQueryRequest("corr-q", "inst1", DateTimeOffset.UtcNow);
+        siteActor.Tell(request);
+
+        dmProbe.ExpectMsg<DeploymentStateQueryRequest>(msg => msg.CorrelationId == "corr-q");
+    }
+
     [Fact]
     public void IntegrationCall_WithoutHandler_ReturnsFailure()
     {