fix(store-and-forward): inline ordered replication dispatch; Warning + counter on replication failures

src/ZB.MOM.WW.ScadaBridge.SiteRuntime/Actors/SiteReplicationActor.cs

@@ -2,6 +2,7 @@ using Akka.Actor;
 using Akka.Cluster;
 using Akka.Event;
 using Microsoft.Extensions.Logging;
+using ZB.MOM.WW.ScadaBridge.Commons.Observability;
 using ZB.MOM.WW.ScadaBridge.SiteRuntime.Deployment;
 using ZB.MOM.WW.ScadaBridge.SiteRuntime.Messages;
 using ZB.MOM.WW.ScadaBridge.SiteRuntime.Persistence;
@@ -140,7 +141,12 @@ public class SiteReplicationActor : ReceiveActor
     {
         if (_peerAddress == null)
         {
-            _logger.LogDebug("No peer available, dropping replication message {Type}", message.GetType().Name);
+            // A dropped op is a lost delta — surface it at Warning + a metric so a
+            // never-tracked peer (a dead standby) is visible, not silent (arch
+            // review 02). In single-node dev the peer is legitimately absent; the
+            // per-op warning is rate-tolerable (accepted per review).
+            ScadaBridgeTelemetry.RecordReplicationFailure();
+            _logger.LogWarning("No peer available, dropping replication message {Type}", message.GetType().Name);
             return;
         }