Enhance mini program environment configuration and chapter loading logic

- Introduced a debugging environment configuration in app.js, allowing for dynamic API endpoint selection based on the environment.
- Implemented lazy loading for chapter parts in chapters.js, improving performance by only fetching necessary data.
- Updated UI elements in chapters.wxml to reflect changes in chapter loading and added loading indicators.
- Enhanced error handling and data management for chapter retrieval, ensuring a smoother user experience.
- Added functionality for switching API environments in settings.js, visible only in development mode.

miniprogram/pages/read/read.js

@@ -76,7 +76,7 @@ Page({
   },
 
   async onLoad(options) {
-    wx.showShareMenu({ withShareTimeline: true })
+    wx.showShareMenu({ menus: ['shareAppMessage', 'shareTimeline'] })
 
     // 预加载 linkTags、linkedMiniprograms（供 onLinkTagTap 用密钥查 appId）
     if (!app.globalData.linkTagsConfig || !app.globalData.linkedMiniprograms) {
@@ -697,6 +697,15 @@ Page({
     }
   },
 
+  // 底部「分享到朋友圈」按钮点击：微信不支持 button open-type=shareTimeline，只能通过右上角菜单分享，点击时引导用户
+  onShareTimelineTap() {
+    wx.showToast({
+      title: '请点击右上角「...」→ 分享到朋友圈',
+      icon: 'none',
+      duration: 2500
+    })
+  },
+
   // 分享到朋友圈：带文章标题，过长时截断（朋友圈卡片标题显示有限）
   onShareTimeline() {
     const { section, sectionId, sectionMid, chapterTitle } = this.data

miniprogram/pages/read/read.wxml

@@ -85,10 +85,10 @@
         <!-- 分享操作区 -->
         <view class="action-section">
           <view class="action-row-inline">
-            <button class="action-btn-inline btn-share-inline" open-type="shareTimeline">
+            <view class="action-btn-inline btn-share-inline" bindtap="onShareTimelineTap">
               <text class="action-icon-small">📣</text>
               <text class="action-text-small">分享到朋友圈</text>
-            </button>
+            </view>
             <view class="action-btn-inline btn-poster-inline" bindtap="generatePoster">
               <text class="action-icon-small">🖼️</text>
               <text class="action-text-small">生成海报</text>