AI 接入 V1.0

UI更新

lib/widgets/category_picker_grid.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
 
 import '../models/category.dart';
+import 'cute_icon.dart';
 
 /// 分类 emoji 宫格（手动记账页与账单编辑页共用）
 ///
@@ -67,7 +68,7 @@ class CategoryPickerGrid extends StatelessWidget {
               ),
             ),
             alignment: Alignment.center,
-            child: Text(category.icon, style: const TextStyle(fontSize: 24)),
+            child: CuteIcon(category.icon, size: 26),
           ),
           const SizedBox(height: 4),
           Text(