♻️ refactor(admin): 优化日期处理逻辑

- 引入dayjs库替代原生Date对象处理日期格式化
- 修改tradeDate字段为dayjs对象以统一日期处理方式
- 标准化日期显示格式为'YYYY-MM-DD HH:mm:ss'
- 统一交易日期和创建时间的日期格式化方式

src/client/admin/pages/StockXunlianCodesPage.tsx

@@ -1,5 +1,6 @@
 import React, { useState, useEffect } from 'react';
 import { Table, Button, Modal, Form, Input, DatePicker, Space, Typography, message, Tag } from 'antd';
+import dayjs from 'dayjs';
 import { PlusOutlined, EditOutlined, DeleteOutlined, SearchOutlined } from '@ant-design/icons';
 import { stockXunlianCodesClient } from '@/client/api';
 import type { InferResponseType, InferRequestType } from 'hono/client';
@@ -87,7 +88,7 @@ export const StockXunlianCodesPage: React.FC = () => {
       name: record.name,
       type: record.type || undefined,
       description: record.description || undefined,
-      tradeDate: record.tradeDate ? new Date(record.tradeDate) : null,
+      tradeDate: record.tradeDate ? dayjs(record.tradeDate) : null,
     });
     setIsModalVisible(true);
   };
@@ -202,13 +203,13 @@ export const StockXunlianCodesPage: React.FC = () => {
       title: '交易日期',
       dataIndex: 'tradeDate',
       key: 'tradeDate',
-      render: (date: string) => date ? new Date(date).toLocaleString() : '-',
+      render: (date: string) => date ? dayjs(date).format('YYYY-MM-DD HH:mm:ss') : '-',
     },
     {
       title: '创建时间',
       dataIndex: 'createdAt',
       key: 'createdAt',
-      render: (date: string) => new Date(date).toLocaleString(),
+      render: (date: string) => dayjs(date).format('YYYY-MM-DD HH:mm:ss'),
     },
     {
       title: '操作',