Improve gateway reliability and client e2e coverage

src/MxGateway.Tests/Gateway/Workers/WorkerClientTests.cs

@@ -166,7 +166,8 @@ public sealed class WorkerClientTests
         await pipePair.DisposeWorkerSideAsync();
 
         await WaitUntilAsync(
-            () => client.State == WorkerClientState.Faulted,
+            () => client.State == WorkerClientState.Faulted
+                && metrics.GetSnapshot().WorkersRunning == 0,
             TestTimeout);
 
         GatewayMetricsSnapshot snapshot = metrics.GetSnapshot();
@@ -174,6 +175,22 @@ public sealed class WorkerClientTests
         Assert.Equal(1, snapshot.WorkerExits);
     }
 
+    [Fact]
+    public async Task DisposeAsync_WhenPipeReadIsBlocked_ReturnsWithinBoundedTimeout()
+    {
+        await using PipePair pipePair = await PipePair.CreateAsync();
+        WorkerClient client = CreateClient(pipePair);
+        await CompleteHandshakeAsync(client, pipePair);
+
+        DateTimeOffset startedAt = DateTimeOffset.UtcNow;
+        await client.DisposeAsync().AsTask().WaitAsync(TestTimeout);
+        TimeSpan elapsed = DateTimeOffset.UtcNow - startedAt;
+
+        Assert.True(
+            elapsed < TimeSpan.FromSeconds(4),
+            $"DisposeAsync took {elapsed.TotalMilliseconds:N0}ms.");
+    }
+
     [Fact]
     public async Task ReadLoop_WhenHeartbeatArrives_UpdatesLastHeartbeatAndWorkerProcess()
     {