feat(user): 修改帮助中心联系客服入口为直连微信客服

- 替换原跳转页面逻辑，使用微信 Button 组件直接调起微信客服
- 设置 Button 关键属性 openType、sessionFrom、showMessageCard、sendMessageTitle 和 onContact 回调
- 重置 Button 样式保持原视觉，调整高度、内边距和圆角
- 从 @tarojs/components 中引入 Button 组件
- 提醒微信客服 Button 在开发者工具无效，需真机预览测试

src/pages/user/help-center/index.tsx

@@ -1,5 +1,5 @@
 import React, { useState } from 'react'
-import { View, Text, ScrollView } from '@tarojs/components'
+import { View, Text, ScrollView, Button } from '@tarojs/components'
 import Taro from '@tarojs/taro'
 import EmptyState from '@/components/common/EmptyState'
 
@@ -127,14 +127,25 @@ const HelpCenterPage: React.FC = () => {
             </View>
           ))}
 
-          {/* 联系客服入口 */}
-          <View
-            className='bg-white rounded-lg p-4 flex items-center justify-center gap-2 mt-3'
-            onClick={() => Taro.navigateTo({ url: '/pages/user/customer-service/index' })}
+          {/* 联系客服入口 - 直接进入微信客服 */}
+          <Button
+            openType="contact"
+            sessionFrom="help_center"
+            showMessageCard
+            sendMessageTitle="欢迎咨询"
+            onContact={(e: any) => console.log('客服会话回调:', e.detail)}
+            className='bg-white rounded-lg w-full mt-3 flex items-center justify-center gap-2'
+            style={{
+              height: 'auto',
+              lineHeight: 'normal',
+              padding: '16px',
+              border: 'none',
+              borderRadius: '8px',
+            }}
           >
             <Text className='text-xl'>📞</Text>
             <Text className='text-sm text-blue-500'>联系在线客服</Text>
-          </View>
+          </Button>
 
           <View className='h-4'></View>
         </View>