feat: 优化推广中心入口+修复API

1. 我的页面：添加推广中心入口卡片
2. 推广中心：去掉邀请码显示，改名推广中心
3. 阅读页：去掉底部推广提示（已移到我的页面）
4. 修复PM2启动配置（PORT=3006）

miniprogram/pages/my/my.wxss

@@ -777,3 +777,66 @@
 .bottom-space {
   height: 40rpx;
 }
+
+/* ===== 推广入口卡片 ===== */
+.promo-entry-card {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  margin: 24rpx 24rpx 0;
+  padding: 32rpx;
+  background: linear-gradient(135deg, rgba(255, 215, 0, 0.15) 0%, rgba(255, 165, 0, 0.1) 100%);
+  border: 2rpx solid rgba(255, 215, 0, 0.3);
+  border-radius: 24rpx;
+}
+
+.promo-entry-left {
+  display: flex;
+  align-items: center;
+  gap: 20rpx;
+}
+
+.promo-entry-icon {
+  width: 80rpx;
+  height: 80rpx;
+  background: rgba(255, 215, 0, 0.2);
+  border-radius: 50%;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  font-size: 36rpx;
+}
+
+.promo-entry-info {
+  display: flex;
+  flex-direction: column;
+  gap: 4rpx;
+}
+
+.promo-entry-title {
+  font-size: 30rpx;
+  color: #ffffff;
+  font-weight: 600;
+}
+
+.promo-entry-desc {
+  font-size: 24rpx;
+  color: rgba(255, 255, 255, 0.5);
+}
+
+.promo-entry-right {
+  display: flex;
+  align-items: center;
+  gap: 16rpx;
+}
+
+.promo-entry-earnings {
+  font-size: 32rpx;
+  color: #FFD700;
+  font-weight: 600;
+}
+
+.promo-entry-arrow {
+  font-size: 28rpx;
+  color: #FFD700;
+}