Remove all migration logic, scroll tutorial targets into view, mock URL uses device ID

- Remove legacy migration code: profiles→automations key fallbacks, segments array
  fallback, standby_interval compat, profile_id compat, wled→led type mapping,
  legacy calibration field, audio CSS migration, default template migration,
  loadTargets alias, wled sub-tab mapping
- Scroll tutorial step targets into view when off-screen
- Mock device URL changed from mock://{led_count} to mock://{device_id},
  hide mock URL badge on device cards

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

server/src/wled_controller/static/js/app.js

@@ -93,7 +93,7 @@ import {
     showAddDevice, closeAddDeviceModal, scanForDevices, handleAddDevice,
 } from './features/device-discovery.js';
 import {
-    loadTargetsTab, loadTargets, switchTargetSubTab,
+    loadTargetsTab, switchTargetSubTab,
     showTargetEditor, closeTargetEditorModal, forceCloseTargetEditorModal, saveTargetEditor,
     startTargetProcessing, stopTargetProcessing,
     startTargetOverlay, stopTargetOverlay, deleteTarget,
@@ -330,7 +330,6 @@ Object.assign(window, {
 
     // targets
     loadTargetsTab,
-    loadTargets,
     switchTargetSubTab,
     expandAllTargetSections, collapseAllTargetSections,
     showTargetEditor,