feat: 申诉常见理由快捷选择 + 证据截图上传

- 后端: 新增 appeal_reason_type, appeal_evidence_urls 字段
- 后端: 新建 upload_routes.py 图片上传接口
- 前端: history 页面添加快捷理由选择器 + 截图上传
- 前端: admin-review 页面展示证据图片 + 点击预览
- 新增 SQL 更新脚本 update_appeal_fields.sql

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

miniprogram/utils/request.js

@@ -4,6 +4,11 @@ function getBaseURL() {
   return app.globalData.baseURL || 'http://127.0.0.1:5000/api'
 }
 
+function getServerBase() {
+  const baseURL = getBaseURL()
+  return baseURL.replace('/api', '')
+}
+
 function getToken() {
   return app.globalData.token || wx.getStorageSync('token') || ''
 }
@@ -53,6 +58,36 @@ function request({ url, method = 'GET', data = {}, header = {} }) {
   })
 }
 
-module.exports = {
-  request
+function uploadFile(filePath) {
+  return new Promise((resolve, reject) => {
+    const token = getToken()
+    wx.uploadFile({
+      url: `${getServerBase()}/api/upload/image`,
+      filePath,
+      name: 'file',
+      header: {
+        Authorization: token ? `Bearer ${token}` : ''
+      },
+      success: (res) => {
+        const data = JSON.parse(res.data || '{}')
+        if (data.code === 0) {
+          resolve(data.data)
+          return
+        }
+        const message = data.message || '上传失败'
+        wx.showToast({ title: message, icon: 'none' })
+        reject(new Error(message))
+      },
+      fail: (err) => {
+        const msg = (err && err.errMsg) || '上传失败'
+        wx.showToast({ title: msg, icon: 'none' })
+        reject(err)
+      }
+    })
+  })
+}
+
+module.exports = {
+  request,
+  uploadFile
 }