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/features/targets.js

@@ -259,7 +259,7 @@ export async function showTargetEditor(targetId = null, cloneData = null) {
             const opt = document.createElement('option');
             opt.value = d.id;
             opt.dataset.name = d.name;
-            const shortUrl = d.url ? d.url.replace(/^https?:\/\//, '') : '';
+            const shortUrl = d.url && d.url.startsWith('http') ? d.url.replace(/^https?:\/\//, '') : '';
             const devType = (d.device_type || 'wled').toUpperCase();
             opt.textContent = `${d.name} [${devType}]${shortUrl ? ' (' + shortUrl + ')' : ''}`;
             deviceSelect.appendChild(opt);