Fix websocket replay tests

tests/test_local_server_unit.py

@@ -694,7 +694,17 @@ class TestLocalServerMoreCoverage:
         assert queue.get_nowait() == "existing"
 
     @pytest.mark.asyncio
-    async def test_mark_route_activity_triggers_notification(self, server_with_no_apps):
+    async def test_handle_session_data_marks_activity(self, server_with_no_apps, monkeypatch):
+        ws = MagicMock()
+        ws.send_bytes = AsyncMock()
+        server_with_no_apps._websocket_connections["rk"] = ws
+        server_with_no_apps._route_last_activity["rk"] = 0.0
+
+        await server_with_no_apps.handle_session_data("rk", b"data")
+        assert server_with_no_apps._route_last_activity["rk"] > 0.0
+        ws.send_bytes.assert_awaited_once_with(b"data")
+
+    def test_mark_route_activity_triggers_notification(self, server_with_no_apps):
         """Test that mark_route_activity triggers SSE notification."""
         import asyncio