feat(dashboard): mirror events via SessionEventDistributor subscriber (fixes dark feed without gRPC client)

src/ZB.MOM.WW.MxGateway.Server/Sessions/SessionManager.cs

@@ -27,6 +27,7 @@ public sealed class SessionManager : ISessionManager
     private readonly SemaphoreSlim _sessionSlots;
     private readonly Grpc.MxAccessGrpcMapper _eventMapper;
     private readonly ILogger<SessionEventDistributor> _distributorLogger;
+    private readonly Dashboard.Hubs.IDashboardEventBroadcaster? _dashboardEventBroadcaster;
 
     /// <summary>
     /// Initializes a new instance of <see cref="SessionManager"/>.
@@ -39,6 +40,12 @@ public sealed class SessionManager : ISessionManager
     /// <param name="logger">Logger.</param>
     /// <param name="eventMapper">Mapper used by each session's event distributor to map worker events to public events.</param>
     /// <param name="distributorLogger">Logger passed to each session's event distributor pump.</param>
+    /// <param name="dashboardEventBroadcaster">
+    ///     Dashboard SignalR fan-out sink. Each session registers an internal distributor
+    ///     subscriber (Task 6) that mirrors raw session events to this broadcaster, so the
+    ///     dashboard receives events regardless of whether a gRPC client is streaming. Null in
+    ///     unit tests that do not exercise the dashboard mirror.
+    /// </param>
     public SessionManager(
         ISessionRegistry registry,
         ISessionWorkerClientFactory workerClientFactory,
@@ -47,7 +54,8 @@ public sealed class SessionManager : ISessionManager
         TimeProvider? timeProvider = null,
         ILogger<SessionManager>? logger = null,
         Grpc.MxAccessGrpcMapper? eventMapper = null,
-        ILogger<SessionEventDistributor>? distributorLogger = null)
+        ILogger<SessionEventDistributor>? distributorLogger = null,
+        Dashboard.Hubs.IDashboardEventBroadcaster? dashboardEventBroadcaster = null)
     {
         _registry = registry ?? throw new ArgumentNullException(nameof(registry));
         _workerClientFactory = workerClientFactory ?? throw new ArgumentNullException(nameof(workerClientFactory));
@@ -57,6 +65,7 @@ public sealed class SessionManager : ISessionManager
         _logger = logger ?? NullLogger<SessionManager>.Instance;
         _eventMapper = eventMapper ?? new Grpc.MxAccessGrpcMapper();
         _distributorLogger = distributorLogger ?? NullLogger<SessionEventDistributor>.Instance;
+        _dashboardEventBroadcaster = dashboardEventBroadcaster;
         _options = options.Value;
         _sessionSlots = new SemaphoreSlim(_options.Sessions.MaxSessions, _options.Sessions.MaxSessions);
     }
@@ -451,7 +460,8 @@ public sealed class SessionManager : ISessionManager
             _options.Events,
             _distributorLogger,
             _timeProvider,
-            _metrics);
+            _metrics,
+            _dashboardEventBroadcaster);
 
         return new GatewaySession(
             sessionId,