perf(worker): signal-driven event drain — removes the 25 ms latency floor and idle wakeups

src/ZB.MOM.WW.MxGateway.Worker/MxAccess/MxAccessStaSession.cs

@@ -455,6 +455,12 @@ public sealed class MxAccessStaSession : IWorkerRuntimeSession
         return eventQueue.Drain(maxEvents, maxTotalBytes);
     }
 
+    /// <inheritdoc />
+    public Task WaitForEventsAsync(TimeSpan timeout, CancellationToken cancellationToken)
+    {
+        return eventQueue.WaitForEventsAsync(timeout, cancellationToken);
+    }
+
     /// <inheritdoc />
     public WorkerFault? DrainFault()
     {