add timeline edit/delete

lib/services/data_service.dart

@@ -466,6 +466,17 @@ class DataService extends ChangeNotifier {
     }
   }
 
+  Future<void> deleteTimelineBlock({
+    required int blockId,
+  }) async {
+    try {
+      await api.delete('/event/delete/$blockId');
+    } catch (e) {
+      debugPrint('Failed to delete timeline block $blockId: $e');
+      rethrow;
+    }
+  }
+
   void clear() {
     _homepageStats = null;
     _legs = [];