feat(deploy): RefreshDeploymentAsync send method

Add CommunicationService.RefreshDeploymentAsync — the typed send method
for the small notify-and-fetch wire message (RefreshDeploymentCommand).
Mirrors DeployInstanceAsync exactly: SiteEnvelope + Ask<DeploymentStatusResponse>
bounded by DeploymentTimeout. CentralCommunicationActor needs no change
(HandleSiteEnvelope is fully generic — all SiteEnvelope messages forward
to /user/site-communication without a per-type switch). Adds a parallel
routing test asserting the envelope reaches the site ClusterClient.

tests/ZB.MOM.WW.ScadaBridge.Communication.Tests/CentralCommunicationActorTests.cs

@@ -101,6 +101,25 @@ public class CentralCommunicationActorTests : TestKit
         Assert.Equal("dep1", ((DeployInstanceCommand)msg.Message).DeploymentId);
     }
 
+    [Fact]
+    public void ClusterClientRouting_RefreshDeploymentCommand_RoutesToSite()
+    {
+        var site = CreateSite("site1", "akka.tcp://scadabridge@host:8082");
+        var (actor, _, siteProbes) = CreateActorWithMockRepo(new[] { site });
+
+        Thread.Sleep(1000);
+
+        var command = new RefreshDeploymentCommand(
+            "dep1", "inst1", "rev1", "admin", DateTimeOffset.UtcNow,
+            "https://central:9000", "tok1");
+        actor.Tell(new SiteEnvelope("site1", command));
+
+        var msg = siteProbes["site1"].ExpectMsg<ClusterClient.Send>();
+        Assert.Equal("/user/site-communication", msg.Path);
+        Assert.IsType<RefreshDeploymentCommand>(msg.Message);
+        Assert.Equal("dep1", ((RefreshDeploymentCommand)msg.Message).DeploymentId);
+    }
+
     [Fact]
     public void UnconfiguredSite_MessageIsDropped()
     {