feat: 支持章节通过 mid 进行访问，优化阅读跳转逻辑。新增章节数据结构，包含章节的 mid 信息，提升用户体验。更新 API 以支持通过 mid 查询章节内容，确保兼容性与灵活性。

miniprogram/pages/purchases/purchases.js

@@ -22,11 +22,24 @@ Page({
   async loadOrders() {
     this.setData({ loading: true })
     try {
-      // 模拟订单数据
-      const purchasedSections = app.globalData.purchasedSections || []
+      let purchasedSections = app.globalData.purchasedSections || []
+      let sectionMidMap = app.globalData.sectionMidMap || {}
+      const userId = app.globalData.userInfo?.id
+      if (userId) {
+        try {
+          const res = await app.request(`/api/miniprogram/user/purchase-status?userId=${encodeURIComponent(userId)}`)
+          if (res?.success && res.data) {
+            purchasedSections = res.data.purchasedSections || []
+            sectionMidMap = res.data.sectionMidMap || {}
+            app.globalData.purchasedSections = purchasedSections
+            app.globalData.sectionMidMap = sectionMidMap
+          }
+        } catch (_) { /* 使用缓存 */ }
+      }
       const orders = purchasedSections.map((id, index) => ({
         id: `order_${index}`,
         sectionId: id,
+        mid: sectionMidMap[id] || 0,
         title: `章节 ${id}`,
         amount: 1,
         status: 'completed',
@@ -42,7 +55,9 @@ Page({
 
   goToRead(e) {
     const id = e.currentTarget.dataset.id
-    wx.navigateTo({ url: `/pages/read/read?id=${id}` })
+    const mid = e.currentTarget.dataset.mid
+    const q = mid ? `mid=${mid}` : `id=${id}`
+    wx.navigateTo({ url: `/pages/read/read?${q}` })
   },
 
   goBack() { wx.navigateBack() },