feat: 海报生成功能+推广优化

1. 阅读页：
   - 添加"生成海报"和"分享给好友"按钮
   - 海报包含章节摘要+邀请码+小程序码占位
   - 优化推广提示区域，添加推广中心入口

2. 分销中心：
   - 完善海报生成功能（推广海报）
   - 去掉"更多分享方式"，改为"复制朋友圈文案"
   - 添加"分享给好友"小程序卡片按钮

3. 分享链接自动带分销ID

miniprogram/pages/referral/referral.js

@@ -29,7 +29,11 @@ Page({
     convertedBindings: [],
     expiredBindings: [],
     currentBindings: [],
-    totalBindings: 0
+    totalBindings: 0,
+    
+    // 海报
+    showPosterModal: false,
+    isGeneratingPoster: false
   },
 
   onLoad() {
@@ -133,10 +137,152 @@ Page({
     })
   },
 
-  // 生成海报
-  generatePoster() {
-    wx.showToast({ title: '海报功能开发中', icon: 'none' })
+  // 生成推广海报
+  async generatePoster() {
+    wx.showLoading({ title: '生成中...' })
+    this.setData({ showPosterModal: true, isGeneratingPoster: true })
+    
+    try {
+      const ctx = wx.createCanvasContext('promoPosterCanvas', this)
+      const { referralCode, userInfo, earnings, referralCount, distributorShare } = this.data
+      
+      // 海报尺寸 300x450
+      const width = 300
+      const height = 450
+      
+      // 背景渐变
+      const grd = ctx.createLinearGradient(0, 0, 0, height)
+      grd.addColorStop(0, '#0f0c29')
+      grd.addColorStop(0.5, '#302b63')
+      grd.addColorStop(1, '#24243e')
+      ctx.setFillStyle(grd)
+      ctx.fillRect(0, 0, width, height)
+      
+      // 顶部装饰
+      ctx.setFillStyle('#FFD700')
+      ctx.fillRect(0, 0, width, 5)
+      
+      // 标题
+      ctx.setFillStyle('#FFD700')
+      ctx.setFontSize(20)
+      ctx.fillText('📚 Soul创业派对', 20, 45)
+      
+      // 副标题
+      ctx.setFillStyle('rgba(255,255,255,0.8)')
+      ctx.setFontSize(12)
+      ctx.fillText('来自派对房的真实商业故事', 20, 70)
+      
+      // 书籍介绍区域
+      ctx.setFillStyle('rgba(255,255,255,0.05)')
+      ctx.fillRect(15, 90, width - 30, 100)
+      
+      ctx.setFillStyle('#ffffff')
+      ctx.setFontSize(14)
+      ctx.fillText('✨ 62个真实商业案例', 25, 115)
+      ctx.fillText('💡 私域运营实战经验', 25, 140)
+      ctx.fillText('🎯 从0到1创业方法论', 25, 165)
+      
+      // 推广者信息
+      ctx.setFillStyle('#00CED1')
+      ctx.setFontSize(13)
+      ctx.fillText(`推荐人: ${userInfo?.nickname || '创业者'}`, 20, 220)
+      
+      // 统计数据
+      ctx.setFillStyle('rgba(255,255,255,0.6)')
+      ctx.setFontSize(11)
+      ctx.fillText(`已推荐 ${referralCount} 人 · 累计收益 ¥${parseFloat(earnings || 0).toFixed(0)}`, 20, 245)
+      
+      // 优惠信息
+      ctx.setFillStyle('rgba(255,215,0,0.15)')
+      ctx.fillRect(15, 265, width - 30, 50)
+      ctx.setFillStyle('#FFD700')
+      ctx.setFontSize(14)
+      ctx.fillText('🎁 专属福利', 25, 290)
+      ctx.setFillStyle('#ffffff')
+      ctx.setFontSize(12)
+      ctx.fillText('通过此码购买立享5%优惠', 25, 308)
+      
+      // 底部区域
+      ctx.setFillStyle('rgba(0,206,209,0.1)')
+      ctx.fillRect(0, height - 110, width, 110)
+      
+      // 邀请码
+      ctx.setFillStyle('#ffffff')
+      ctx.setFontSize(12)
+      ctx.fillText('我的邀请码', 20, height - 85)
+      ctx.setFillStyle('#00CED1')
+      ctx.setFontSize(22)
+      ctx.fillText(referralCode, 20, height - 55)
+      
+      // 小程序码占位
+      ctx.setFillStyle('#ffffff')
+      ctx.beginPath()
+      ctx.arc(width - 55, height - 55, 40, 0, Math.PI * 2)
+      ctx.fill()
+      ctx.setFillStyle('#00CED1')
+      ctx.setFontSize(9)
+      ctx.fillText('扫码', width - 62, height - 55)
+      ctx.fillText('购买', width - 62, height - 42)
+      
+      // 底部提示
+      ctx.setFillStyle('rgba(255,255,255,0.5)')
+      ctx.setFontSize(10)
+      ctx.fillText(`推广返利 ${distributorShare}%`, 20, height - 20)
+      
+      ctx.draw(true, () => {
+        wx.hideLoading()
+        this.setData({ isGeneratingPoster: false })
+      })
+    } catch (e) {
+      console.error('生成海报失败:', e)
+      wx.hideLoading()
+      wx.showToast({ title: '生成失败', icon: 'none' })
+      this.setData({ showPosterModal: false, isGeneratingPoster: false })
+    }
   },
+  
+  // 关闭海报弹窗
+  closePosterModal() {
+    this.setData({ showPosterModal: false })
+  },
+  
+  // 保存海报
+  savePoster() {
+    wx.canvasToTempFilePath({
+      canvasId: 'promoPosterCanvas',
+      success: (res) => {
+        wx.saveImageToPhotosAlbum({
+          filePath: res.tempFilePath,
+          success: () => {
+            wx.showToast({ title: '已保存到相册', icon: 'success' })
+            this.setData({ showPosterModal: false })
+          },
+          fail: (err) => {
+            if (err.errMsg.includes('auth deny')) {
+              wx.showModal({
+                title: '提示',
+                content: '需要相册权限才能保存海报',
+                confirmText: '去设置',
+                success: (res) => {
+                  if (res.confirm) {
+                    wx.openSetting()
+                  }
+                }
+              })
+            } else {
+              wx.showToast({ title: '保存失败', icon: 'none' })
+            }
+          }
+        })
+      },
+      fail: () => {
+        wx.showToast({ title: '生成图片失败', icon: 'none' })
+      }
+    }, this)
+  },
+  
+  // 阻止冒泡
+  stopPropagation() {},
 
   // 分享到朋友圈
   shareToMoments() {

miniprogram/pages/referral/referral.wxml

@@ -172,23 +172,47 @@
         <text class="share-arrow">→</text>
       </view>
       
-      <view class="share-item" bindtap="shareToMoments">
+      <button class="share-item share-btn-wechat" open-type="share">
         <view class="share-icon wechat">💬</view>
         <view class="share-info">
-          <text class="share-title">分享到朋友圈</text>
-          <text class="share-desc">复制文案发朋友圈</text>
+          <text class="share-title">分享给好友</text>
+          <text class="share-desc">直接发送小程序卡片</text>
         </view>
         <text class="share-arrow">→</text>
-      </view>
+      </button>
       
-      <view class="share-item" bindtap="copyLink">
-        <view class="share-icon link">🔗</view>
+      <view class="share-item" bindtap="shareToMoments">
+        <view class="share-icon link">📝</view>
         <view class="share-info">
-          <text class="share-title">更多分享方式</text>
-          <text class="share-desc">使用系统分享功能</text>
+          <text class="share-title">复制朋友圈文案</text>
+          <text class="share-desc">一键复制推广文案</text>
         </view>
         <text class="share-arrow">→</text>
       </view>
     </view>
   </view>
+
+  <!-- 海报生成弹窗 -->
+  <view class="modal-overlay" wx:if="{{showPosterModal}}" bindtap="closePosterModal">
+    <view class="modal-content poster-modal" catchtap="stopPropagation">
+      <view class="modal-header">
+        <text class="modal-title">推广海报</text>
+        <view class="modal-close" bindtap="closePosterModal">✕</view>
+      </view>
+
+      <!-- 海报预览 -->
+      <view class="poster-preview">
+        <canvas canvas-id="promoPosterCanvas" class="poster-canvas" style="width: 300px; height: 450px;"></canvas>
+      </view>
+
+      <view class="poster-actions">
+        <view class="poster-btn btn-save" bindtap="savePoster">
+          <text class="btn-icon">💾</text>
+          <text>保存到相册</text>
+        </view>
+      </view>
+
+      <text class="poster-tip">保存后可分享到朋友圈或发送给好友</text>
+    </view>
+  </view>
 </view>

miniprogram/pages/referral/referral.wxss

@@ -111,4 +111,22 @@
 .share-title { font-size: 28rpx; color: #fff; font-weight: 500; display: block; }
 .share-desc { font-size: 22rpx; color: rgba(255,255,255,0.5); margin-top: 4rpx; display: block; }
 .share-arrow { font-size: 28rpx; color: rgba(255,255,255,0.3); }
-.share-btn { line-height: normal; font-size: inherit; }
+.share-btn-wechat { line-height: normal; font-size: inherit; }
+
+/* 弹窗 */
+.modal-overlay { position: fixed; inset: 0; background: rgba(0,0,0,0.7); backdrop-filter: blur(20rpx); display: flex; align-items: flex-end; justify-content: center; z-index: 1000; }
+.modal-content { width: 100%; max-width: 750rpx; background: #1c1c1e; border-radius: 48rpx 48rpx 0 0; padding: 48rpx; padding-bottom: calc(48rpx + env(safe-area-inset-bottom)); animation: slideUp 0.3s ease; }
+@keyframes slideUp { from { transform: translateY(100%); } to { transform: translateY(0); } }
+.modal-header { display: flex; align-items: center; justify-content: space-between; margin-bottom: 32rpx; }
+.modal-title { font-size: 36rpx; font-weight: 600; color: #fff; }
+.modal-close { width: 64rpx; height: 64rpx; border-radius: 50%; background: rgba(255,255,255,0.1); display: flex; align-items: center; justify-content: center; font-size: 28rpx; color: rgba(255,255,255,0.6); }
+
+/* 海报弹窗 */
+.poster-modal { padding-bottom: calc(64rpx + env(safe-area-inset-bottom)); }
+.poster-preview { display: flex; justify-content: center; margin: 32rpx 0; padding: 24rpx; background: rgba(0,0,0,0.3); border-radius: 24rpx; }
+.poster-canvas { border-radius: 16rpx; box-shadow: 0 16rpx 48rpx rgba(0,0,0,0.5); }
+.poster-actions { display: flex; gap: 24rpx; margin-bottom: 24rpx; }
+.poster-btn { flex: 1; display: flex; align-items: center; justify-content: center; gap: 12rpx; padding: 28rpx; border-radius: 24rpx; font-size: 30rpx; font-weight: 500; color: #fff; }
+.btn-save { background: linear-gradient(135deg, #00CED1 0%, #20B2AA 100%); }
+.btn-icon { font-size: 32rpx; }
+.poster-tip { font-size: 24rpx; color: rgba(255,255,255,0.4); text-align: center; display: block; }