HA integration: fix reload loop, parallel device fetch, WS guards, translations

- Fix indentation bug causing scenes device to not register
- Use nonlocal tracking to prevent infinite reload loops on target/scene changes
- Guard WS start/stop to avoid redundant connections
- Parallel device brightness fetching via asyncio.gather
- Route set_leds service to correct coordinator by source ID
- Remove stale pattern cache, reuse single timeout object
- Fix translations structure for light/select entities
- Unregister service when last config entry unloaded

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

custom_components/wled_screen_controller/translations/ru.json

@@ -31,6 +31,11 @@
         "name": "{scene_name}"
       }
     },
+    "light": {
+      "api_input_light": {
+        "name": "Подсветка"
+      }
+    },
     "switch": {
       "processing": {
         "name": "Обработка"
@@ -58,9 +63,12 @@
         "name": "Яркость"
       }
     },
-    "light": {
-      "light": {
-        "name": "Подсветка"
+    "select": {
+      "color_strip_source": {
+        "name": "Источник цветовой полосы"
+      },
+      "brightness_source": {
+        "name": "Источник яркости"
       }
     }
   }