Replace profile targets with scene activation and searchable scene selector

Profiles now activate scene presets instead of individual targets, with
configurable deactivation behavior (none/revert/fallback scene). The
target checklist UI is replaced by a searchable combobox for scene
selection that scales well with many scenes.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/wled_controller/main.py

@@ -108,8 +108,14 @@ async def lifespan(app: FastAPI):
     mqtt_service = MQTTService(config.mqtt)
     set_mqtt_service(mqtt_service)
 
-    # Create profile engine (needs processor_manager + mqtt_service)
-    profile_engine = ProfileEngine(profile_store, processor_manager, mqtt_service=mqtt_service)
+    # Create profile engine (needs processor_manager + mqtt_service + stores for scene activation)
+    profile_engine = ProfileEngine(
+        profile_store, processor_manager,
+        mqtt_service=mqtt_service,
+        scene_preset_store=scene_preset_store,
+        target_store=picture_target_store,
+        device_store=device_store,
+    )
 
     # Create auto-backup engine
     auto_backup_engine = AutoBackupEngine(