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/css/components.css

@@ -414,6 +414,15 @@ textarea:focus-visible {
     box-shadow: 0 0 0 2px rgba(76, 175, 80, 0.2);
 }
 
+/* WS device connection URL */
+.ws-url-row {
+    display: flex;
+    gap: 6px;
+}
+.ws-url-row input { flex: 1; }
+.ws-url-row .btn { padding: 4px 10px; min-width: 0; flex: 0 0 auto; }
+.endpoint-label { display: block; font-weight: 600; margin-bottom: 2px; opacity: 0.7; font-size: 0.8em; }
+
 /* Scene target selector */
 .scene-target-add-row {
     display: flex;