Add advanced path management, debug logging, and fix channel sync

New features:
- In-app debug log viewer with copy/clear functionality
- Advanced path management UI with history and custom path builder
- Battery indicator widget with voltage/percentage toggle
- Contact/channel filtering and sorting improvements
- Repeater command ACK tracking with path history integration

Fixes:
- Switch channel sync from parallel to sequential to prevent timeouts
- Preserve path overrides when contacts refresh from device
- Fix ACK hash computation for SMAZ-encoded messages
- Proper cleanup of pending operations on disconnect

lib/services/app_settings_service.dart

@@ -2,6 +2,7 @@ import 'dart:convert';
 import 'package:flutter/foundation.dart';
 import '../models/app_settings.dart';
 import '../storage/prefs_manager.dart';
+import '../utils/app_logger.dart';
 
 class AppSettingsService extends ChangeNotifier {
   static const String _settingsKey = 'app_settings';
@@ -112,6 +113,12 @@ class AppSettingsService extends ChangeNotifier {
     await updateSettings(_settings.copyWith(themeMode: value));
   }
 
+  Future<void> setAppDebugLogEnabled(bool value) async {
+    await updateSettings(_settings.copyWith(appDebugLogEnabled: value));
+    // Update the global logger
+    appLogger.setEnabled(value);
+  }
+
   Future<void> setBatteryChemistryForDevice(String deviceId, String chemistry) async {
     final updated = Map<String, String>.from(_settings.batteryChemistryByDeviceId);
     updated[deviceId] = chemistry;