add new traction page

lib/services/dataService.dart

@@ -235,6 +235,23 @@ class DataService extends ChangeNotifier {
     }
   }
 
+  Future<dynamic> createLoco(Map<String, dynamic> payload) async {
+    try {
+      final response = await api.put('/loco/new', payload);
+      final locoClass = payload['class']?.toString();
+      if (locoClass != null &&
+          locoClass.isNotEmpty &&
+          !_locoClasses.contains(locoClass)) {
+        _locoClasses = [..._locoClasses, locoClass];
+      }
+      _notifyAsync();
+      return response;
+    } catch (e) {
+      debugPrint('Failed to create loco: $e');
+      rethrow;
+    }
+  }
+
   Future<void> fetchOnThisDay({DateTime? date}) async {
     _isOnThisDayLoading = true;
     final target = date ?? DateTime.now();