refactor(admin): 用已安装的 file-saver/fast-deep-equal 替代手写下载与 JSON 比较

apps/admin/src/hooks/useDirtyGuard.ts

@@ -1,6 +1,7 @@
 import { useCallback, useRef } from 'react';
 import { App } from 'antd';
 import type { FormInstance } from 'antd';
+import equal from 'fast-deep-equal';
 
 /**
  * 弹窗「未保存内容」保护：关闭弹窗时若表单值已被修改，先确认再关闭，
@@ -15,16 +16,16 @@ import type { FormInstance } from 'antd';
  */
 export function useDirtyGuard(form: FormInstance) {
   const { modal } = App.useApp();
-  const pristineRef = useRef<string>('');
+  const pristineRef = useRef<unknown>(null);
 
   /** 记录当前表单值为「未修改」基准；打开弹窗/回填后调用 */
   const snapshot = useCallback(() => {
-    pristineRef.current = JSON.stringify(form.getFieldsValue());
+    pristineRef.current = form.getFieldsValue();
   }, [form]);
 
   /** 表单是否有未保存修改（与 snapshot 时对比） */
   const isDirty = useCallback(() => {
-    return JSON.stringify(form.getFieldsValue()) !== pristineRef.current;
+    return !equal(form.getFieldsValue(), pristineRef.current);
   }, [form]);
 
   const confirmClose = useCallback(