✨ feat(opportunities): 优化预计成交日期选择组件

- 将原生date输入框替换为Ant Design的DatePicker组件
- 添加日期格式化显示(YYYY-MM-DD)
- 增加占位提示文本"请选择预计成交日期"
- 支持日期选择框清空操作

src/client/admin/pages/Opportunities.tsx

@@ -1,6 +1,6 @@
 import React, { useState } from 'react';
 import {
-  Button, Table, Space, Form, Input, InputNumber, Select, Modal, Card, Typography, Popconfirm, Tag,
+  Button, Table, Space, Form, Input, InputNumber, Select, Modal, Card, Typography, Popconfirm, Tag, DatePicker,
   App
 } from 'antd';
 import { useQuery } from '@tanstack/react-query';
@@ -394,7 +394,11 @@ export const OpportunitiesPage = () => {
             label="预计成交日期"
             rules={[{ required: false, message: '请选择预计成交日期' }]}
           >
-            <Input type="date" />
+            <DatePicker
+              format="YYYY-MM-DD"
+              placeholder="请选择预计成交日期"
+              allowClear
+            />
           </Form.Item>
 
           <Form.Item