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/utils/app_logger.dart

@@ -0,0 +1,55 @@
+import '../services/app_debug_log_service.dart';
+
+/// Global app logger instance
+/// Usage: appLogger.info('Message', tag: 'MyClass');
+class AppLogger {
+  AppDebugLogService? _service;
+  bool _enabled = false;
+
+  /// Initialize the logger with the debug log service
+  void initialize(AppDebugLogService service, {bool enabled = false}) {
+    _service = service;
+    _enabled = enabled;
+    _service?.setEnabled(enabled);
+  }
+
+  /// Update whether logging is enabled
+  void setEnabled(bool enabled) {
+    _enabled = enabled;
+    _service?.setEnabled(enabled);
+  }
+
+  /// Check if logging is currently enabled
+  bool get isEnabled => _enabled;
+
+  /// Log an info message
+  void info(String message, {String tag = 'App'}) {
+    if (_enabled && _service != null) {
+      _service!.info(message, tag: tag);
+    }
+  }
+
+  /// Log a warning message
+  void warn(String message, {String tag = 'App'}) {
+    if (_enabled && _service != null) {
+      _service!.warn(message, tag: tag);
+    }
+  }
+
+  /// Log an error message
+  void error(String message, {String tag = 'App'}) {
+    if (_enabled && _service != null) {
+      _service!.error(message, tag: tag);
+    }
+  }
+
+  /// Log a message with custom level
+  void log(String message, {String tag = 'App', AppDebugLogLevel level = AppDebugLogLevel.info}) {
+    if (_enabled && _service != null) {
+      _service!.log(message, tag: tag, level: level);
+    }
+  }
+}
+
+/// Global logger instance
+final appLogger = AppLogger();