fix(feishu): add extra_ua_tags=["channel"] to FeishuWSClient for group @mention delivery

Without this UA tag the Feishu server does not push group @mention events
over the WebSocket transport. The "channel" tag tells the server to use
the Channel protocol which enables group-message routing in addition to P2P
direct messages.

Root cause: FeishuWSClient was created without any UA signaling tag, so the
server defaulted to the basic DM-only push mode. Group @mention events were
silently dropped before reaching Hermes.

Fixes https://github.com/NousResearch/hermes-agent/issues/50656

Also adds a regression test verifying the UA tag is present in the
FeishuWSClient constructor call.

plugins/platforms/feishu/adapter.py

@@ -4730,6 +4730,12 @@ class FeishuAdapter(BasePlatformAdapter):
             log_level=lark.LogLevel.INFO,
             event_handler=self._event_handler,
             domain=domain,
+            # Channel SDK signaling tag: without this UA tag the Feishu
+            # server does not push group @mention events over the WebSocket
+            # transport.  The tag tells the server to use the Channel protocol
+            # which enables group-message routing in addition to P2P DM.
+            # See https://github.com/NousResearch/hermes-agent/issues/50656
+            extra_ua_tags=["channel"],
         )
         self._ws_future = loop.run_in_executor(
             None,

tests/gateway/test_feishu.py

@@ -414,6 +414,65 @@ class TestFeishuAdapterMessaging(unittest.TestCase):
         self.assertEqual(sleeps, [1])
         self.assertEqual(fake_loop.calls, 2)
 
+    @patch.dict(os.environ, {
+        "FEISHU_APP_ID": "cli_app",
+        "FEISHU_APP_SECRET": "secret_app",
+    }, clear=True)
+    def test_connect_websocket_sets_channel_ua_tag(self):
+        """Verify that FeishuWSClient receives extra_ua_tags=["channel"].
+
+        Without this UA tag the Feishu server does not push group @mention
+        events over the WebSocket transport.  See
+        https://github.com/NousResearch/hermes-agent/issues/50656
+        """
+        from gateway.config import PlatformConfig
+        from plugins.platforms.feishu.adapter import FeishuAdapter
+
+        adapter = FeishuAdapter(PlatformConfig())
+        ws_client = SimpleNamespace()
+
+        with (
+            patch("plugins.platforms.feishu.adapter.FEISHU_AVAILABLE", True),
+            patch("plugins.platforms.feishu.adapter.FEISHU_WEBSOCKET_AVAILABLE", True),
+            patch("plugins.platforms.feishu.adapter.lark",
+                  SimpleNamespace(LogLevel=SimpleNamespace(INFO="INFO", WARNING="WARNING"))),
+            patch("plugins.platforms.feishu.adapter.EventDispatcherHandler") as mock_handler_class,
+            patch("plugins.platforms.feishu.adapter.FeishuWSClient") as mock_ws_client,
+            patch("plugins.platforms.feishu.adapter._run_official_feishu_ws_client"),
+            patch("plugins.platforms.feishu.adapter.acquire_scoped_lock", return_value=(True, None)),
+            patch("plugins.platforms.feishu.adapter.release_scoped_lock"),
+            patch.object(adapter, "_hydrate_bot_identity", new=AsyncMock()),
+            patch.object(adapter, "_build_lark_client", return_value=SimpleNamespace()),
+        ):
+            _mock_event_dispatcher_builder(mock_handler_class)
+
+            loop = asyncio.new_event_loop()
+            future = loop.create_future()
+            future.set_result(None)
+
+            class _Loop:
+                def run_in_executor(self, *_args, **_kwargs):
+                    return future
+                def is_closed(self):
+                    return False
+
+            try:
+                with patch("plugins.platforms.feishu.adapter.asyncio.get_running_loop",
+                           return_value=_Loop()):
+                    connected = asyncio.run(adapter.connect())
+            finally:
+                loop.close()
+
+        self.assertTrue(connected)
+        # Verify the Channel SDK UA tag is present — this is the fix for
+        # group @mention message delivery over WebSocket.
+        mock_ws_client.assert_called_once()
+        call_kwargs = mock_ws_client.call_args.kwargs
+        self.assertIn("extra_ua_tags", call_kwargs,
+                      "FeishuWSClient must receive extra_ua_tags for group @mention delivery")
+        self.assertEqual(call_kwargs["extra_ua_tags"], ["channel"],
+                         "extra_ua_tags must be ['channel'] to enable group event routing")
+
     @patch.dict(os.environ, {}, clear=True)
     def test_edit_message_updates_existing_feishu_message(self):
         from gateway.config import PlatformConfig