some issues fixed

lib/models/overview_favourite.dart

@@ -16,6 +16,8 @@ class OverviewFavourite {
     this.flow = TxFlowFilter.expense,
     this.barStyle = LabelChartBarStyle.parallel,
     this.invertExpensePerspective = false,
+    this.updatedAt = 0,
+    this.deleted = false,
   });
 
   final String id;
@@ -34,6 +36,12 @@ class OverviewFavourite {
   final LabelChartBarStyle barStyle;
   final bool invertExpensePerspective;
 
+  /// Epoch ms; used for last-write-wins sync across devices.
+  final int updatedAt;
+
+  /// Soft-delete so removals propagate via sync instead of being recreated.
+  final bool deleted;
+
   OverviewFavourite copyWith({
     String? id,
     String? name,
@@ -44,6 +52,9 @@ class OverviewFavourite {
     TxFlowFilter? flow,
     LabelChartBarStyle? barStyle,
     bool? invertExpensePerspective,
+    int? updatedAt,
+    bool? deleted,
+    bool touchUpdatedAt = false,
   }) {
     return OverviewFavourite(
       id: id ?? this.id,
@@ -56,6 +67,10 @@ class OverviewFavourite {
       barStyle: barStyle ?? this.barStyle,
       invertExpensePerspective:
           invertExpensePerspective ?? this.invertExpensePerspective,
+      updatedAt: touchUpdatedAt
+          ? DateTime.now().millisecondsSinceEpoch
+          : (updatedAt ?? this.updatedAt),
+      deleted: deleted ?? this.deleted,
     );
   }
 
@@ -69,9 +84,18 @@ class OverviewFavourite {
         'flow': flow.name,
         'barStyle': barStyle.name,
         'invertExpensePerspective': invertExpensePerspective,
+        'updatedAt': updatedAt,
+        'deleted': deleted,
       };
 
   factory OverviewFavourite.fromJson(Map<String, dynamic> json) {
+    final rawUpdated = json['updatedAt'] ?? json['updated_at'];
+    final updatedAt = switch (rawUpdated) {
+      int n => n,
+      num n => n.round(),
+      String s => int.tryParse(s) ?? 0,
+      _ => 0,
+    };
     return OverviewFavourite(
       id: json['id'] as String? ?? 'fav_${DateTime.now().millisecondsSinceEpoch}',
       name: (json['name'] as String?)?.trim().isNotEmpty == true
@@ -100,6 +124,8 @@ class OverviewFavourite {
       ),
       invertExpensePerspective:
           json['invertExpensePerspective'] as bool? ?? false,
+      updatedAt: updatedAt,
+      deleted: json['deleted'] as bool? ?? false,
     );
   }
 }
@@ -107,3 +133,25 @@ class OverviewFavourite {
 enum OverviewMetricMode { flow, labels }
 
 enum OverviewPeriodMode { monthly, yearly }
+
+/// Union favourites by id with last-write-wins on [OverviewFavourite.updatedAt].
+List<OverviewFavourite> mergeOverviewFavourites(
+  List<OverviewFavourite> local,
+  List<OverviewFavourite> remote,
+) {
+  final byId = <String, OverviewFavourite>{};
+  void put(OverviewFavourite fav) {
+    final existing = byId[fav.id];
+    if (existing == null || fav.updatedAt >= existing.updatedAt) {
+      byId[fav.id] = fav;
+    }
+  }
+
+  for (final fav in remote) {
+    put(fav);
+  }
+  for (final fav in local) {
+    put(fav);
+  }
+  return byId.values.toList(growable: false);
+}