feat: Implement command queue for BLE command handling

- Added BleCommandQueue to manage command serialization and responses in BleCommandSender.
- Updated writeData, writeDataAndWaitForAck, and writeDataAndWaitForResponse methods to utilize the command queue.
- Enhanced BleResponseHandler to complete commands based on responses received from the BLE device.
- Introduced new commands for channel management, including getChannel and setChannel.
- Created LocationTrailLayer and TrailControls widgets for displaying and managing location trails on the map.
- Added PermissionRequestDialog to handle location permission requests on app startup.
- Updated LocationTrackingService to allow GPS tracking without a BLE connection.

lib/providers/map_provider.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/foundation.dart';
 import 'package:latlong2/latlong.dart';
+import '../models/location_trail.dart';
 
 class MapProvider with ChangeNotifier {
   LatLng? _targetLocation;
@@ -9,11 +10,22 @@ class MapProvider with ChangeNotifier {
   // Track which contact paths are currently visible
   final Set<String> _visibleContactPaths = {};
 
+  // Location trail tracking
+  LocationTrail? _currentTrail;
+  bool _isTrailVisible = true;
+  final List<LocationTrail> _trailHistory = [];
+
   LatLng? get targetLocation => _targetLocation;
   double? get targetZoom => _targetZoom;
   bool get shouldAnimate => _shouldAnimate;
   Set<String> get visibleContactPaths => Set.unmodifiable(_visibleContactPaths);
 
+  // Trail getters
+  LocationTrail? get currentTrail => _currentTrail;
+  bool get isTrailVisible => _isTrailVisible;
+  List<LocationTrail> get trailHistory => List.unmodifiable(_trailHistory);
+  bool get isTrailActive => _currentTrail?.isActive ?? false;
+
   void navigateToLocation({
     required LatLng location,
     double zoom = 15.0,
@@ -64,4 +76,80 @@ class MapProvider with ChangeNotifier {
     _visibleContactPaths.add(publicKeyHex);
     notifyListeners();
   }
+
+  /// Start a new location trail
+  void startTrail() {
+    // End current trail if active
+    if (_currentTrail != null && _currentTrail!.isActive) {
+      endTrail();
+    }
+
+    _currentTrail = LocationTrail(
+      id: DateTime.now().millisecondsSinceEpoch.toString(),
+      startTime: DateTime.now(),
+    );
+    _isTrailVisible = true;
+    notifyListeners();
+  }
+
+  /// Add a point to the current trail
+  void addTrailPoint(LatLng position, {double? accuracy, double? speed}) {
+    if (_currentTrail == null || !_currentTrail!.isActive) {
+      startTrail();
+    }
+
+    _currentTrail!.addPoint(TrailPoint(
+      position: position,
+      timestamp: DateTime.now(),
+      accuracy: accuracy,
+      speed: speed,
+    ));
+    notifyListeners();
+  }
+
+  /// End the current trail
+  void endTrail() {
+    if (_currentTrail != null) {
+      _currentTrail!.isActive = false;
+      _currentTrail!.endTime = DateTime.now();
+      if (_currentTrail!.points.isNotEmpty) {
+        _trailHistory.add(_currentTrail!);
+      }
+      _currentTrail = null;
+      notifyListeners();
+    }
+  }
+
+  /// Toggle trail visibility
+  void toggleTrailVisibility() {
+    _isTrailVisible = !_isTrailVisible;
+    notifyListeners();
+  }
+
+  /// Clear the current trail
+  void clearCurrentTrail() {
+    if (_currentTrail != null) {
+      _currentTrail = null;
+      notifyListeners();
+    }
+  }
+
+  /// Clear all trail history
+  void clearAllTrails() {
+    _currentTrail = null;
+    _trailHistory.clear();
+    notifyListeners();
+  }
+
+  /// Get total trail distance in meters
+  double get totalTrailDistance {
+    if (_currentTrail == null) return 0;
+    return _currentTrail!.totalDistance;
+  }
+
+  /// Get trail duration
+  Duration get trailDuration {
+    if (_currentTrail == null) return Duration.zero;
+    return _currentTrail!.duration;
+  }
 }