refactor: key colors targets → CSS source type, HA target improvements

Key Colors refactor:
- New `key_colors` CSS source type with inline rectangles
- KeyColorsColorStripStream: extracts N colors from screen regions
- CSS editor: EntitySelect for picture source, IconSelect for color mode
- Configure Regions button on card opens pattern canvas editor
- Live WS preview at 5 FPS with rectangle overlay + color swatches
- Removed KC target type, pattern template entity, and related API routes
- Removed KC/pattern template sections from Targets tab

HA light target improvements:
- Update rate, transition, mappings, brightness VS now editable via PUT
- Card crosslinks for HA source, CSS source, brightness VS
- HA connection status icon, text metrics (Hz, uptime)
- Brightness value source selector in editor

server/tests/storage/test_output_target_store.py

@@ -5,9 +5,6 @@ import pytest
 from wled_controller.storage.output_target import OutputTarget
 from wled_controller.storage.output_target_store import OutputTargetStore
 from wled_controller.storage.wled_output_target import WledOutputTarget
-from wled_controller.storage.key_colors_output_target import (
-    KeyColorsOutputTarget,
-)
 
 
 @pytest.fixture
@@ -37,18 +34,17 @@ class TestOutputTargetModel:
         assert isinstance(target, WledOutputTarget)
         assert target.device_id == "dev_1"
 
-    def test_key_colors_from_dict(self):
+    def test_key_colors_type_rejected(self):
+        """key_colors target type removed — from_dict raises ValueError."""
         data = {
             "id": "pt_2",
             "name": "KC Target",
             "target_type": "key_colors",
-            "picture_source_id": "ps_1",
-            "settings": {},
             "created_at": "2025-01-01T00:00:00+00:00",
             "updated_at": "2025-01-01T00:00:00+00:00",
         }
-        target = OutputTarget.from_dict(data)
-        assert isinstance(target, KeyColorsOutputTarget)
+        with pytest.raises(ValueError, match="Unknown target type"):
+            OutputTarget.from_dict(data)
 
     def test_unknown_type_raises(self):
         data = {
@@ -82,14 +78,10 @@ class TestOutputTargetStoreCRUD:
         assert t.name == "LED 1"
         assert store.count() == 1
 
-    def test_create_key_colors_target(self, store):
-        t = store.create_target(
-            name="KC 1",
-            target_type="key_colors",
-            picture_source_id="ps_1",
-        )
-        assert isinstance(t, KeyColorsOutputTarget)
-        assert t.picture_source_id == "ps_1"
+    def test_create_key_colors_target_rejected(self, store):
+        """key_colors target type is no longer supported (migrated to CSS source)."""
+        with pytest.raises(ValueError, match="Invalid target type"):
+            store.create_target(name="KC 1", target_type="key_colors")
 
     def test_create_invalid_type(self, store):
         with pytest.raises(ValueError, match="Invalid target type"):
@@ -194,11 +186,13 @@ class TestOutputTargetQueries:
 class TestOutputTargetPersistence:
     def test_persist_and_reload(self, tmp_path):
         from wled_controller.storage.database import Database
+
         db_path = str(tmp_path / "ot_persist.db")
         db = Database(db_path)
         s1 = OutputTargetStore(db)
         t = s1.create_target(
-            "Persist", "led",
+            "Persist",
+            "led",
             device_id="dev_1",
             fps=60,
             tags=["tv"],

server/tests/test_processor_manager.py

@@ -2,7 +2,10 @@
 
 import pytest
 
-from wled_controller.core.processing.processor_manager import ProcessorDependencies, ProcessorManager
+from wled_controller.core.processing.processor_manager import (
+    ProcessorDependencies,
+    ProcessorManager,
+)
 
 
 @pytest.fixture
@@ -230,8 +233,6 @@ def test_get_target_metrics(processor_manager):
 
 def test_target_type_detection(processor_manager):
     """Test target type detection via processor instances."""
-    from wled_controller.storage.key_colors_output_target import KeyColorsSettings
-    from wled_controller.core.processing.kc_target_processor import KCTargetProcessor
     from wled_controller.core.processing.wled_target_processor import WledTargetProcessor
 
     processor_manager.add_device(
@@ -245,13 +246,6 @@ def test_target_type_detection(processor_manager):
         device_id="test_device",
     )
 
-    processor_manager.add_kc_target(
-        target_id="kc_target",
-        picture_source_id="src_1",
-        settings=KeyColorsSettings(),
-    )
-
-    assert isinstance(processor_manager._processors["kc_target"], KCTargetProcessor)
     assert isinstance(processor_manager._processors["wled_target"], WledTargetProcessor)