feat(item): 添加物品编辑功能- 在 AddItemScreen 中添加编辑物品的功能

- 接受一个可选的 Item 对象用于编辑
- 在初始化时加载物品的现有数据
- 更新 ItemListScreen 中的编辑按钮，使其导航到 AddItemScreen 并传递要编辑的物品

lib/screens/item_list_screen.dart

@@ -52,7 +52,7 @@ class _ItemListScreenState extends State<ItemListScreen> {
                       Navigator.push(
                         context,
                         MaterialPageRoute(
-                          builder: (context) => DetailItemScreen(item: item),
+                          builder: (context) => AddItemScreen(itemToEdit: item),
                         ),
                       );
                     },

lib/screens/item_screens/add_item_screen.dart

@@ -41,8 +41,14 @@ extension ItemIsUseX on ItemIsUse {
 }
 
 class AddItemScreen extends StatefulWidget {
+  final Item? itemToEdit;
+
+  const AddItemScreen({Key? key, this.itemToEdit}) : super(key: key);
+
   @override
   _FromTestRouteSate createState() => _FromTestRouteSate();
+
+
 }
 
 class _FromTestRouteSate extends State<AddItemScreen> {
@@ -59,6 +65,17 @@ class _FromTestRouteSate extends State<AddItemScreen> {
   // 添加自定义分类列表
   List<String> _categories = ['A', 'B', 'C', 'D']; // 自定义分类
 
+  @override
+  void initState() {
+    super.initState();
+    final item = widget.itemToEdit;
+    if (item != null) {
+      _name = item.name;
+      _description = item.description!;
+      _selectedDate = item.purchaseDate;
+    }
+  }
+
   @override
   Widget build(BuildContext context) {
     return Scaffold(