fix(server): flush outbound queue before closing ports + silence CI trace spam

src/GaudiHTTP.IntegrationTests.End2End/H11/ServerStartupReliabilitySpec.cs

@@ -84,6 +84,7 @@ public async Task Server_with_three_listeners_should_respond_to_first_h11_reques
         }
         finally
         {
+            Servus.Senf.Tracing.Disable();
             cert.Dispose();
         }
     }

src/GaudiHTTP/Streams/Stages/Server/HttpServerConnectionStageLogic.cs

@@ -523,6 +523,15 @@ private void CloseAllPorts()
             Cancel(_inResponse);
         }
 
+        if (_outboundQueue.Count > 0)
+        {
+            // Outbound data is still queued (e.g. response encoded but not yet pushed
+            // because the network outlet had no demand). Drain via the flush path so
+            // the data reaches the transport before the connection closes.
+            CompleteAfterFlushingOutbound();
+            return;
+        }
+
         if (!IsClosed(_outNetwork))
         {
             Complete(_outNetwork);