add timeline

lib/services/dataService.dart

@@ -49,6 +49,12 @@ class DataService extends ChangeNotifier {
   bool get isTractionLoading => _isTractionLoading;
   bool _tractionHasMore = false;
   bool get tractionHasMore => _tractionHasMore;
+  final Map<int, List<LocoAttrVersion>> _locoTimelines = {};
+  final Map<int, bool> _isLocoTimelineLoading = {};
+  List<LocoAttrVersion> timelineForLoco(int locoId) =>
+      _locoTimelines[locoId] ?? [];
+  bool isLocoTimelineLoading(int locoId) =>
+      _isLocoTimelineLoading[locoId] ?? false;
 
   // Trips
   List<TripSummary> _trips = [];
@@ -235,6 +241,24 @@ class DataService extends ChangeNotifier {
     }
   }
 
+  Future<List<LocoAttrVersion>> fetchLocoTimeline(int locoId) async {
+    _isLocoTimelineLoading[locoId] = true;
+    _notifyAsync();
+    try {
+      final json = await api.get('/loco/get-timeline/$locoId');
+      final timeline = LocoAttrVersion.fromGroupedJson(json);
+      _locoTimelines[locoId] = timeline;
+      return timeline;
+    } catch (e) {
+      debugPrint('Failed to fetch loco timeline for $locoId: $e');
+      _locoTimelines[locoId] = [];
+      return [];
+    } finally {
+      _isLocoTimelineLoading[locoId] = false;
+      _notifyAsync();
+    }
+  }
+
   Future<dynamic> createLoco(Map<String, dynamic> payload) async {
     try {
       final response = await api.put('/loco/new', payload);
@@ -424,6 +448,8 @@ class DataService extends ChangeNotifier {
     _trips = [];
     _tripDetails = [];
     _eventFields = [];
+    _locoTimelines.clear();
+    _isLocoTimelineLoading.clear();
     _notifyAsync();
   }