修复autoOfflineTime时间问题：

1. 后端编辑API添加autoOfflineTime字段更新
2. 修复前端时间计算错误（移除错误的+8小时偏移）
3. 后端返回时间字段保持原样不做额外处理

Reject.js

@@ -1353,7 +1353,7 @@ app.put('/api/supplies/:id/edit', async (req, res) => {
     try {
         const connection = await pool.getConnection();
         const productId = req.params.id;
-        const { productName, price, costprice, quantity, grossWeight, yolk, specification, supplyStatus, description, region, contactId, producting, imageUrls } = req.body;
+        const { productName, price, costprice, quantity, grossWeight, yolk, specification, supplyStatus, description, region, contactId, producting, imageUrls, autoOfflineTime } = req.body;
 
         // 开始事务
         await connection.beginTransaction();
@@ -1463,7 +1463,7 @@ app.put('/api/supplies/:id/edit', async (req, res) => {
             SET productName = ?, price = ?, costprice = ?, quantity = ?, grossWeight = ?, 
                 yolk = ?, specification = ?, producting = ?, supplyStatus = ?, description = ?, region = ?, 
                 product_contact = ?, contact_phone = ?, imageUrls = ?, 
-                autoOfflineHours = ?, updated_at = ?
+                autoOfflineTime = ?, autoOfflineHours = ?, updated_at = ?
             WHERE id = ?
         `;
 
@@ -1471,6 +1471,7 @@ app.put('/api/supplies/:id/edit', async (req, res) => {
             productName, price.toString(), costprice || '', quantityValue, grossWeight,
             yolk, specification, producting, supplyStatus, description, region, 
             productContact, contactPhone, JSON.stringify(uploadedImageUrls),
+            autoOfflineTime || null, // 自动下架时间
             req.body.autoOfflineHours || 24, // 默认24小时
             new Date(), // 更新updated_at字段
             productId

supply.html

@@ -5944,6 +5944,13 @@
             // 计算自动下架时间（当前时间 + 分钟数）
             const autoOfflineTime = new Date();
             autoOfflineTime.setMinutes(autoOfflineTime.getMinutes() + minutes);
+            // 格式化为数据库存储的北京时间格式 (YYYY-MM-DD HH:mm:ss)
+            const autoOfflineTimeStr = autoOfflineTime.getFullYear() + '-' + 
+                String(autoOfflineTime.getMonth() + 1).padStart(2, '0') + '-' + 
+                String(autoOfflineTime.getDate()).padStart(2, '0') + ' ' + 
+                String(autoOfflineTime.getHours()).padStart(2, '0') + ':' + 
+                String(autoOfflineTime.getMinutes()).padStart(2, '0') + ':' + 
+                String(autoOfflineTime.getSeconds()).padStart(2, '0');
             
             const formData = {
                 productName: document.getElementById('productName').value,
@@ -5966,7 +5973,7 @@
                 sellerId: userInfo.userId, // 添加当前登录用户的userId作为sellerId
                 autoOfflineDays: null, // 不再使用天数，设置为null
                 autoOfflineHours: autoOfflineHours,
-                autoOfflineTime: autoOfflineTime.toISOString()
+                autoOfflineTime: autoOfflineTimeStr
             };
             
             // 验证表单
@@ -7785,7 +7792,13 @@
                 // 计算自动下架时间（当前时间 + 分钟数）
                 const autoOfflineTime = new Date();
                 autoOfflineTime.setMinutes(autoOfflineTime.getMinutes() + minutes);
-                const autoOfflineTimeISO = autoOfflineTime.toISOString();
+                // 格式化为数据库存储的北京时间格式 (YYYY-MM-DD HH:mm:ss)
+                const autoOfflineTimeStr = autoOfflineTime.getFullYear() + '-' + 
+                    String(autoOfflineTime.getMonth() + 1).padStart(2, '0') + '-' + 
+                    String(autoOfflineTime.getDate()).padStart(2, '0') + ' ' + 
+                    String(autoOfflineTime.getHours()).padStart(2, '0') + ':' + 
+                    String(autoOfflineTime.getMinutes()).padStart(2, '0') + ':' + 
+                    String(autoOfflineTime.getSeconds()).padStart(2, '0');
                 
                 const formData = {
                     productName: document.getElementById('editProductName').value,
@@ -7805,7 +7818,7 @@
                     contactId: document.getElementById('editContactId').value,
                     freshness: document.getElementById('editFreshness').value,
                     imageUrls: editCurrentImages, // 添加编辑后的图片列表
-                    autoOfflineTime: autoOfflineTimeISO, // 自动下架时间
+                    autoOfflineTime: autoOfflineTimeStr, // 自动下架时间
                     autoOfflineDays: null, // 不再使用天数，设置为null
                     autoOfflineHours: autoOfflineHours // 自动下架小时数（分钟转换而来）
                 };