feat(websocket): add WebSocket display backend for browser client

tests/test_controller.py

@@ -83,35 +83,3 @@ class TestStreamControllerCleanup:
         controller.cleanup()
 
         mock_mic_instance.stop.assert_called_once()
-
-
-class TestStreamControllerWarmup:
-    """Tests for StreamController topic warmup."""
-
-    def test_warmup_topics_idempotent(self):
-        """warmup_topics can be called multiple times."""
-        StreamController._topics_warmed = False
-
-        with patch("urllib.request.urlopen") as mock_urlopen:
-            StreamController.warmup_topics()
-            StreamController.warmup_topics()
-
-            assert mock_urlopen.call_count >= 3
-
-    def test_warmup_topics_sets_flag(self):
-        """warmup_topics sets the warmed flag."""
-        StreamController._topics_warmed = False
-
-        with patch("urllib.request.urlopen"):
-            StreamController.warmup_topics()
-
-            assert StreamController._topics_warmed is True
-
-    def test_warmup_topics_skips_after_first(self):
-        """warmup_topics skips after first call."""
-        StreamController._topics_warmed = True
-
-        with patch("urllib.request.urlopen") as mock_urlopen:
-            StreamController.warmup_topics()
-
-            mock_urlopen.assert_not_called()