fix: support offline manual bookkeeping

frontend/lib/features/add/add_page.dart

@@ -188,6 +188,7 @@ class _AddPageState extends State<AddPage> {
         note: _noteCtrl.text.trim().isEmpty ? null : _noteCtrl.text.trim(),
         paymentMethod: _paymentMethod,
         occurredAt: _occurredAt,
+        localFirst: true,
       );
       TransactionEvents.notifyChanged();
       if (mounted) context.pop(amount);

frontend/lib/features/settings/category_manage_page.dart

@@ -65,7 +65,13 @@ class _CategoryManagePageState extends State<CategoryManagePage> {
     final result = await _showEditor();
     if (result == null) return;
     try {
-      await CategoryApi.create(result.name, result.icon, result.color, _type);
+      await CategoryApi.create(
+        result.name,
+        result.icon,
+        result.color,
+        _type,
+        localFirst: true,
+      );
       await _load();
     } catch (error) {
       if (mounted) _showError(error);
@@ -82,6 +88,7 @@ class _CategoryManagePageState extends State<CategoryManagePage> {
         iconKey: result.icon,
         colorKey: result.color,
         sortOrder: category.sortOrder,
+        localFirst: true,
       );
       await _load();
     } catch (error) {
@@ -375,7 +382,7 @@ class _CategoryManagePageState extends State<CategoryManagePage> {
     );
     if (!confirmed) return;
     try {
-      await CategoryApi.delete(category.id);
+      await CategoryApi.delete(category.id, localFirst: true);
       await _load();
     } catch (error) {
       if (mounted) _showError(error);
@@ -410,7 +417,7 @@ class _CategoryManagePageState extends State<CategoryManagePage> {
     final ids = _custom.map((category) => category.id).toList();
     setState(() => _savingOrder = true);
     try {
-      await CategoryApi.reorder(_type, ids);
+      await CategoryApi.reorder(_type, ids, localFirst: true);
       if (!mounted) return;
       setState(() {
         _reordering = false;