Add WebSocket device type, capability-driven settings, hide filter on collapse

- New WS device type: broadcaster singleton + LEDClient that sends binary
  frames to connected WebSocket clients during processing
- FastAPI WS endpoint at /api/v1/devices/{device_id}/ws with token auth
- Frontend: add/edit WS devices, connection URL with copy button in settings
- Add health_check and auto_restore capabilities to WLED and Serial providers;
  hide health interval and auto-restore toggle for devices without them
- Skip health check loop for virtual devices (Mock, MQTT, WS) — set always-online
- Copy buttons and labels for API CSS push endpoints (REST POST / WebSocket)
- Hide mock:// and ws:// URLs in target device dropdown
- Hide filter textbox when card section is collapsed (cs-collapsed CSS class)

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

server/src/wled_controller/static/locales/en.json

@@ -131,6 +131,8 @@
   "device.mqtt_topic": "MQTT Topic:",
   "device.mqtt_topic.hint": "MQTT topic path for publishing pixel data (e.g. mqtt://ledgrab/device/name)",
   "device.mqtt_topic.placeholder": "mqtt://ledgrab/device/living-room",
+  "device.ws_url": "Connection URL:",
+  "device.ws_url.hint": "WebSocket URL for clients to connect and receive LED data",
   "device.url.hint": "IP address or hostname of the device (e.g. http://192.168.1.100)",
   "device.name": "Device Name:",
   "device.name.placeholder": "Living Room TV",