Resolve all 46 low-severity architecture review findings

src/ZB.MOM.WW.ScadaBridge.Host/Actors/AkkaHostedService.cs

@@ -561,18 +561,10 @@ akka {{
         // 30 s timeout, so it could only add a hop and latency to every audit batch.
         centralControlGrpc?.SetAuditIngestActor(auditIngest.Proxy);
 
-        // Hand the proxy to the SiteStreamGrpcServer (if registered on this node)
-        // so the IngestAuditEvents RPC routes incoming site batches to the singleton.
-        // The gRPC server is currently only registered on Site nodes; on a central
-        // node this resolves to null and the wiring is a no-op unless a future
-        // central-hosted gRPC server (or a real site→central client) is added.
-        var grpcServer = _serviceProvider.GetService<ZB.MOM.WW.ScadaBridge.Communication.Grpc.SiteStreamGrpcServer>();
-        grpcServer?.SetAuditIngestActor(auditIngest.Proxy);
+
         _logger.LogInformation(
-            "AuditLogIngestActor singleton created (control-plane bound: {ControlBound}, "
-            + "site-stream server bound: {GrpcBound})",
-            centralControlGrpc is not null,
-            grpcServer is not null);
+            "AuditLogIngestActor singleton created (control-plane bound: {ControlBound})",
+            centralControlGrpc is not null);
 
         // Subscribe the per-site stalled
         // telemetry tracker to the actor system EventStream NOW that the

src/ZB.MOM.WW.ScadaBridge.Host/Actors/ClusterBootstrapCoordinator.cs

@@ -121,8 +121,10 @@ public sealed class ClusterBootstrapCoordinator : IHostedService
                 return;
             }
 
+            ct.ThrowIfCancellationRequested();
             var cluster = Akka.Cluster.Cluster.Get(_system());
             var addresses = order.Select(Address.Parse).ToArray();
+            ct.ThrowIfCancellationRequested();
             cluster.JoinSeedNodes(addresses);
 
             // Peer-first is a one-way commitment: JoinSeedNodeProcess never self-forms. If the founder
@@ -184,7 +186,7 @@ public sealed class ClusterBootstrapCoordinator : IHostedService
             if (await TryConnectAsync(host, port, ct).ConfigureAwait(false)) return true;
             if (sw.Elapsed >= window) return false;
             try { await Task.Delay(interval, ct).ConfigureAwait(false); }
-            catch (OperationCanceledException) { return false; }
+            catch (OperationCanceledException) when (ct.IsCancellationRequested) { throw; }
         }
         return false;
     }