全面优化：小程序 + 后台管理

## 小程序优化
1. 我的页面：
   - 头像点击获取微信头像（button open-type="chooseAvatar"）
   - 昵称点击直接修改
   - 去掉"创业伙伴"图标
   - ID优先显示微信号

2. 设置页面：
   - 一键获取微信手机号
   - 微信号/支付宝绑定优化

## 后台管理优化
1. 内容管理：
   - 章节编辑增加"免费章节"开关
   - 保存时自动去重标题（如#1.2重复）

2. 用户管理：
   - 修复绑定关系显示（优先查referral_bindings表）

app/api/db/users/referrals/route.ts

@@ -1,6 +1,8 @@
 /**
  * 用户绑定关系API
  * 获取指定用户的所有绑定用户列表
+ * 
+ * 优先从referral_bindings表查询，同时兼容users表的referred_by字段
  */
 import { NextResponse } from 'next/server'
 import { query } from '@/lib/db'
@@ -31,55 +33,87 @@ export async function GET(request: Request) {
       code = userRows[0].referral_code
     }
     
-    if (!code) {
-      return NextResponse.json({
-        success: true,
-        referrals: [],
-        stats: {
-          total: 0,
-          purchased: 0,
-          pendingEarnings: 0,
-          totalEarnings: 0
-        }
-      })
+    let referrals: any[] = []
+    
+    // 1. 首先从referral_bindings表查询绑定关系
+    try {
+      const bindingsReferrals = await query(`
+        SELECT 
+          rb.id as binding_id,
+          rb.referee_id,
+          rb.status as binding_status,
+          rb.binding_date,
+          rb.expiry_date,
+          rb.commission_amount,
+          u.id, u.nickname, u.avatar, u.phone, u.open_id,
+          u.has_full_book, u.purchased_sections,
+          u.created_at, u.updated_at,
+          DATEDIFF(rb.expiry_date, NOW()) as days_remaining
+        FROM referral_bindings rb
+        JOIN users u ON rb.referee_id = u.id
+        WHERE rb.referrer_id = ?
+        ORDER BY rb.binding_date DESC
+      `, [userId]) as any[]
+      
+      if (bindingsReferrals.length > 0) {
+        referrals = bindingsReferrals
+      }
+    } catch (e) {
+      console.log('[Referrals] referral_bindings表查询失败，使用users表')
     }
     
-    // 查询通过该推广码绑定的所有用户
-    const referrals = await query(`
-      SELECT 
-        id, nickname, avatar, phone, open_id,
-        has_full_book, purchased_sections,
-        created_at, updated_at
-      FROM users 
-      WHERE referred_by = ?
-      ORDER BY created_at DESC
-    `, [code]) as any[]
+    // 2. 如果referral_bindings表没有数据，再从users表查询
+    if (referrals.length === 0 && code) {
+      referrals = await query(`
+        SELECT 
+          id, nickname, avatar, phone, open_id,
+          has_full_book, purchased_sections,
+          created_at, updated_at,
+          NULL as binding_status,
+          NULL as binding_date,
+          NULL as expiry_date,
+          NULL as days_remaining,
+          NULL as commission_amount
+        FROM users 
+        WHERE referred_by = ?
+        ORDER BY created_at DESC
+      `, [code]) as any[]
+    }
     
     // 统计信息
-    const purchasedCount = referrals.filter(r => r.has_full_book || (r.purchased_sections && r.purchased_sections !== '[]')).length
+    const purchasedCount = referrals.filter(r => 
+      r.has_full_book || 
+      r.binding_status === 'converted' ||
+      (r.purchased_sections && r.purchased_sections !== '[]')
+    ).length
     
     // 查询该用户的收益信息
     const earningsRows = await query(`
       SELECT earnings, pending_earnings, withdrawn_earnings 
-      FROM users WHERE ${userId ? 'id = ?' : 'referral_code = ?'}
-    `, [userId || code]) as any[]
+      FROM users WHERE id = ?
+    `, [userId]) as any[]
     
     const earnings = earningsRows[0] || { earnings: 0, pending_earnings: 0, withdrawn_earnings: 0 }
     
     // 格式化返回数据
     const formattedReferrals = referrals.map(r => ({
-      id: r.id,
+      id: r.referee_id || r.id,
       nickname: r.nickname || '微信用户',
       avatar: r.avatar,
       phone: r.phone ? r.phone.replace(/(\d{3})\d{4}(\d{4})/, '$1****$2') : null,
       hasOpenId: !!r.open_id,
-      hasPurchased: r.has_full_book || (r.purchased_sections && r.purchased_sections !== '[]'),
+      hasPurchased: r.has_full_book || r.binding_status === 'converted' || (r.purchased_sections && r.purchased_sections !== '[]'),
       hasFullBook: !!r.has_full_book,
       purchasedSections: typeof r.purchased_sections === 'string' 
         ? JSON.parse(r.purchased_sections || '[]').length 
         : 0,
-      createdAt: r.created_at,
-      status: r.has_full_book ? 'vip' : (r.purchased_sections && r.purchased_sections !== '[]' ? 'paid' : 'free')
+      createdAt: r.binding_date || r.created_at,
+      bindingStatus: r.binding_status || 'active',
+      daysRemaining: r.days_remaining,
+      commission: parseFloat(r.commission_amount) || 0,
+      status: r.binding_status === 'converted' ? 'converted' 
+        : r.has_full_book ? 'vip' 
+        : (r.purchased_sections && r.purchased_sections !== '[]' ? 'paid' : 'active')
     }))
     
     return NextResponse.json({