Rewrite HAOS integration: target-centric architecture with KC color sensors

- Rewrite integration to target-centric model: each picture target becomes
  a HA device under a server hub with switch, FPS, and status sensors
- Replace KC light entities with color sensors (hex state + RGB attributes)
  for better automation support via WebSocket real-time updates
- Add WebSocket manager for Key Colors color streaming
- Add KC per-stage timing metrics (calc_colors, broadcast) with rolling avg
- Fix KC timing fields missing from API by adding them to Pydantic schema
- Make start/stop processing idempotent to prevent intermittent 404 errors
- Add HAOS localization support (en, ru) using translation_key system
- Rename integration from "WLED Screen Controller" to "LED Screen Controller"
- Remove obsolete select.py (display select) and README.md

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

custom_components/wled_screen_controller/const.py

@@ -1,23 +1,21 @@
-"""Constants for the WLED Screen Controller integration."""
+"""Constants for the LED Screen Controller integration."""
 
 DOMAIN = "wled_screen_controller"
 
 # Configuration
 CONF_SERVER_URL = "server_url"
+CONF_API_KEY = "api_key"
 
 # Default values
 DEFAULT_SCAN_INTERVAL = 10  # seconds
 DEFAULT_TIMEOUT = 10  # seconds
+WS_RECONNECT_DELAY = 5  # seconds
+WS_MAX_RECONNECT_DELAY = 60  # seconds
 
-# Attributes
-ATTR_DEVICE_ID = "device_id"
-ATTR_FPS_ACTUAL = "fps_actual"
-ATTR_FPS_TARGET = "fps_target"
-ATTR_DISPLAY_INDEX = "display_index"
-ATTR_FRAMES_PROCESSED = "frames_processed"
-ATTR_ERRORS_COUNT = "errors_count"
-ATTR_UPTIME = "uptime_seconds"
+# Target types
+TARGET_TYPE_LED = "led"
+TARGET_TYPE_KEY_COLORS = "key_colors"
 
-# Services
-SERVICE_START_PROCESSING = "start_processing"
-SERVICE_STOP_PROCESSING = "stop_processing"
+# Data keys stored in hass.data[DOMAIN][entry_id]
+DATA_COORDINATOR = "coordinator"
+DATA_WS_MANAGER = "ws_manager"