fix: avatar picker uses chooseMedia, COS domain to tx.vsai.net.cn

- Replace chooseAvatar button with chooseMedia (more reliable, works on all versions)
- COS avatar URL uses tx.vsai.net.cn instead of generated bucket domain
- Phone shows '已授权' only (no actual number displayed)

miniprogram/pages/register/register.js

@@ -28,10 +28,18 @@ Page({
     })
   },
 
-  onChooseAvatar: function (e) {
-    if (e.detail && e.detail.avatarUrl) {
-      this.setData({ avatarUrl: e.detail.avatarUrl })
-    }
+  onPickAvatar: function () {
+    var self = this
+    wx.chooseMedia({
+      count: 1,
+      mediaType: ['image'],
+      sourceType: ['album', 'camera'],
+      success: function (res) {
+        if (res.tempFiles && res.tempFiles[0]) {
+          self.setData({ avatarUrl: res.tempFiles[0].tempFilePath })
+        }
+      }
+    })
   },
 
   onNicknameInput: function (e) {

miniprogram/pages/register/register.wxml

@@ -7,10 +7,10 @@
   <view class="page-content">
     <view class="section-title">设置头像</view>
     <view class="avatar-area">
-      <button class="avatar-btn" open-type="chooseAvatar" bindchooseavatar="onChooseAvatar">
+      <view class="avatar-wrap" bindtap="onPickAvatar">
         <image class="avatar-img" src="{{avatarUrl}}" mode="aspectFill"></image>
         <view class="avatar-edit-hint">点击更换</view>
-      </button>
+      </view>
     </view>
 
     <view class="section-title">设置昵称</view>

miniprogram/pages/register/register.wxss

@@ -21,21 +21,12 @@
   margin-bottom: 12rpx;
 }
 
-.avatar-btn {
-  background: none;
-  border: none;
-  padding: 0;
-  margin: 0;
-  line-height: normal;
+.avatar-wrap {
   display: flex;
   flex-direction: column;
   align-items: center;
 }
 
-.avatar-btn::after {
-  border: none;
-}
-
 .avatar-img {
   width: 160rpx;
   height: 160rpx;

server/src/routes/user.js

@@ -50,7 +50,7 @@ router.post('/user/avatar', requireUser, upload.single('file'), wrap(async (req,
       ContentType: req.file.mimetype
     }, (err, data) => err ? reject(err) : resolve(data))
   })
-  const avatarUrl = 'https://' + config.cos.bucket + '.cos.' + config.cos.region + '.myqcloud.com/' + key
+  const avatarUrl = 'https://tx.vsai.net.cn/' + key
   await userDao.updateProfile(req.user.user_id, { nickname: null, avatar: avatarUrl, gender: null })
   res.json(ok({ avatar: avatarUrl }))
 }))