fix: 创建订单前查重-防止同一用户同一套餐重复pending订单

src/handlers/payment.rs

@@ -675,12 +675,28 @@ pub async fn payment_page(
             }
         }
     } else {
-        let new_no = Uuid::new_v4().to_string();
-        let expires_at = pkg.days.map(|d| Utc::now() + chrono::Duration::days(d));
-        db::create_payment_order(
-            pool.get_ref(), claims.user_id, &new_no, &query.package_, pkg.amount, expires_at,
-        ).await?;
-        new_no
+        // 查重：用户是否已有同套餐的待支付订单，有则复用
+        let existing: Option<String> = sqlx::query_scalar(
+            r#"SELECT order_no FROM payment_orders
+               WHERE user_id = $1 AND package_type = $2 AND status = 'pending'
+               ORDER BY created_at DESC LIMIT 1"#,
+        )
+        .bind(claims.user_id)
+        .bind(&query.package_)
+        .fetch_optional(pool.get_ref())
+        .await
+        .map_err(|e| AppError::Database(format!("查询已有订单失败: {}", e)))?;
+
+        if let Some(no) = existing {
+            no
+        } else {
+            let new_no = Uuid::new_v4().to_string();
+            let expires_at = pkg.days.map(|d| Utc::now() + chrono::Duration::days(d));
+            db::create_payment_order(
+                pool.get_ref(), claims.user_id, &new_no, &query.package_, pkg.amount, expires_at,
+            ).await?;
+            new_no
+        }
     };
 
     let base_url = std::env::var("APP_BASE_URL")