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

src/ZB.MOM.WW.MxGateway.Server/Grpc/EventStreamService.cs

@@ -2,7 +2,6 @@ using System.Runtime.CompilerServices;
 using Microsoft.Extensions.Options;
 using ZB.MOM.WW.MxGateway.Contracts.Proto;
 using ZB.MOM.WW.MxGateway.Server.Configuration;
-using ZB.MOM.WW.MxGateway.Server.Dashboard.Hubs;
 using ZB.MOM.WW.MxGateway.Server.Metrics;
 using ZB.MOM.WW.MxGateway.Server.Sessions;
 using ZB.MOM.WW.MxGateway.Server.Workers;
@@ -12,9 +11,7 @@ namespace ZB.MOM.WW.MxGateway.Server.Grpc;
 public sealed class EventStreamService(
     ISessionManager sessionManager,
     IOptions<GatewayOptions> options,
-    GatewayMetrics metrics,
-    IDashboardEventBroadcaster dashboardEventBroadcaster,
-    ILogger<EventStreamService> logger) : IEventStreamService
+    GatewayMetrics metrics) : IEventStreamService
 {
     /// <summary>
     ///     Streams events from a session to the client asynchronously.
@@ -26,8 +23,19 @@ public sealed class EventStreamService(
     ///         <see cref="SessionEventDistributor"/> pump. The pump owns the single drain of
     ///         the worker event stream and the worker→public mapping (mirroring the former
     ///         <c>ProduceEventsAsync</c>); this loop is the per-subscriber boundary that
-    ///         applies the per-RPC filter (<c>AfterWorkerSequence</c>), the dashboard mirror,
-    ///         queue-depth metrics, and the backpressure/overflow policy.
+    ///         applies the per-RPC filter (<c>AfterWorkerSequence</c>), queue-depth metrics,
+    ///         and the backpressure/overflow policy.
+    ///     </para>
+    ///     <para>
+    ///         Task 6 moved the dashboard mirror OFF this per-RPC loop. The dashboard is now a
+    ///         first-class internal subscriber on the session's
+    ///         <see cref="SessionEventDistributor"/> (see <c>GatewaySession.StartDashboardMirror</c>),
+    ///         so it receives session events even when no gRPC client is streaming. This loop no
+    ///         longer mirrors to the dashboard. One deliberate consequence: the dashboard now sees
+    ///         RAW session events, not the per-gRPC-subscriber <c>AfterWorkerSequence</c>-filtered
+    ///         view this loop applies — the dashboard is a separate LDAP-authenticated monitoring
+    ///         view that should see the session's full event activity (per-session dashboard ACL is
+    ///         the separate Task 18).
     ///     </para>
     ///     <para>
     ///         Overflow handling (Task 5): the distributor's per-subscriber channel is bounded
@@ -97,34 +105,12 @@ public sealed class EventStreamService(
 
                 // Per-RPC filter stays at the subscriber boundary: each request may resume
                 // from a different AfterWorkerSequence, so the shared pump fans raw events and
-                // this loop drops the ones at or below the caller's watermark. Filtered events
-                // are not mirrored to the dashboard, matching the pre-Task-4 ordering where
-                // the skip ran before the dashboard Publish.
+                // this loop drops the ones at or below the caller's watermark.
                 if (mxEvent.WorkerSequence <= afterWorkerSequence)
                 {
                     continue;
                 }
 
-                // Mirror the event to the dashboard EventsHub group for this session.
-                // Fire-and-forget — broadcast errors must not affect the source gRPC stream.
-                // Server-041: IDashboardEventBroadcaster documents Publish as never-throw,
-                // but we enforce that at the seam too so a future implementation that adds
-                // synchronous validation or a serializer hop cannot fault this loop and end
-                // the client's gRPC stream. (Task 6 will move this tap onto its own
-                // distributor subscriber; for Task 4 it coexists here, firing once per
-                // delivered event for the single subscriber exactly as before.)
-                try
-                {
-                    dashboardEventBroadcaster.Publish(session.SessionId, mxEvent);
-                }
-                catch (Exception ex)
-                {
-                    logger.LogDebug(
-                        ex,
-                        "Dashboard event mirror threw for session {SessionId}; continuing.",
-                        session.SessionId);
-                }
-
                 // Queue-depth gauge tracks events the pump has fanned into this subscriber's
                 // channel but the client has not yet consumed — the same "buffered, not yet
                 // delivered" quantity the pre-Task-4 per-RPC channel reported. The bounded