优化小程序阅读页面，新增好友优惠展示逻辑，支持通过推荐人获取折扣。调整价格计算方式，确保用户在购买章节时能看到实际优惠。更新相关样式以提升用户体验。

miniprogram/utils/chapterAccessManager.js

@@ -26,17 +26,18 @@ class ChapterAccessManager {
       if (res.success && res.freeChapters) {
         return {
           freeChapters: res.freeChapters,
-          prices: res.prices || { section: 1, fullbook: 9.9 }
+          prices: res.prices || { section: 1, fullbook: 9.9 },
+          userDiscount: (typeof res.userDiscount === 'number' ? res.userDiscount : 5)
         }
       }
     } catch (e) {
       console.warn('[AccessManager] 获取配置失败，使用默认配置:', e)
     }
-    
-    // 默认配置
+
     return {
       freeChapters: ['preface', 'epilogue', '1.1', 'appendix-1', 'appendix-2', 'appendix-3'],
-      prices: { section: 1, fullbook: 9.9 }
+      prices: { section: 1, fullbook: 9.9 },
+      userDiscount: 5
     }
   }