优化阅读页跳转逻辑，优先传递章节中间ID（mid），以提升分享功能的一致性。更新相关页面以支持新逻辑，确保用户体验流畅。增加退款功能的相关处理，支持订单退款及退款原因的记录，增强订单管理的灵活性。

miniprogram/pages/purchases/purchases.js

@@ -26,6 +26,7 @@ Page({
           const orders = (res.data || []).map(item => ({
             id: item.id || item.order_sn,
             sectionId: item.product_id || item.section_id,
+            sectionMid: item.section_mid ?? item.mid ?? 0,
             title: item.product_name || `章节 ${item.product_id || ''}`,
             amount: item.amount || 0,
             status: item.status || 'completed',
@@ -39,6 +40,7 @@ Page({
       const orders = purchasedSections.map((id, index) => ({
         id: `order_${index}`,
         sectionId: id,
+        sectionMid: app.getSectionMid(id),
         title: `章节 ${id}`,
         amount: 1,
         status: 'completed',
@@ -50,7 +52,7 @@ Page({
       const purchasedSections = app.globalData.purchasedSections || []
       this.setData({
         orders: purchasedSections.map((id, i) => ({
-          id: `order_${i}`, sectionId: id, title: `章节 ${id}`, amount: 1, status: 'completed',
+          id: `order_${i}`, sectionId: id, sectionMid: app.getSectionMid(id), title: `章节 ${id}`, amount: 1, status: 'completed',
           createTime: new Date(Date.now() - i * 86400000).toLocaleDateString()
         }))
       })
@@ -61,7 +63,9 @@ Page({
 
   goToRead(e) {
     const id = e.currentTarget.dataset.id
-    wx.navigateTo({ url: `/pages/read/read?id=${id}` })
+    const mid = e.currentTarget.dataset.mid || app.getSectionMid(id)
+    const q = mid ? `mid=${mid}` : `id=${id}`
+    wx.navigateTo({ url: `/pages/read/read?${q}` })
   },
 
   goBack() { wx.navigateBack() },

miniprogram/pages/purchases/purchases.wxml

@@ -15,7 +15,7 @@
     </view>
 
     <view class="orders-list" wx:elif="{{orders.length > 0}}">
-      <view class="order-item" wx:for="{{orders}}" wx:key="id" bindtap="goToRead" data-id="{{item.sectionId}}">
+      <view class="order-item" wx:for="{{orders}}" wx:key="id" bindtap="goToRead" data-id="{{item.sectionId}}" data-mid="{{item.sectionMid}}">
         <view class="order-info">
           <text class="order-title">{{item.title}}</text>
           <text class="order-time">{{item.createTime}}</text>