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/js/app.js

@@ -32,7 +32,7 @@ import {
     showSettings, closeDeviceSettingsModal, forceCloseDeviceSettingsModal,
     saveDeviceSettings, updateBrightnessLabel, saveCardBrightness,
     turnOffDevice, removeDevice, loadDevices,
-    updateSettingsBaudFpsHint,
+    updateSettingsBaudFpsHint, copyWsUrl,
 } from './features/devices.js';
 import {
     loadDashboard, stopUptimeTimer,
@@ -113,6 +113,7 @@ import {
     onAudioVizChange,
     applyGradientPreset,
     cloneColorStrip,
+    copyEndpointUrl,
 } from './features/color-strips.js';
 
 // Layer 5: audio sources
@@ -201,6 +202,7 @@ Object.assign(window, {
     removeDevice,
     loadDevices,
     updateSettingsBaudFpsHint,
+    copyWsUrl,
 
     // dashboard
     loadDashboard,
@@ -368,6 +370,7 @@ Object.assign(window, {
     onAudioVizChange,
     applyGradientPreset,
     cloneColorStrip,
+    copyEndpointUrl,
 
     // audio sources
     showAudioSourceModal,