fix: 修复用户端页面移动端响应式布局问题

- ProductDetail.vue: 添加移动端布局适配
- OrderDetail.vue: 添加移动端布局适配
- Orders.vue: 添加移动端布局适配

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/views/user/Orders.vue

@@ -97,4 +97,28 @@ onMounted(fetchOrders)
 <style scoped lang="scss">
 .orders-page { padding: 0; }
 .table-card { background: #2d2d44; border: 1px solid rgba(255, 255, 255, 0.06); border-radius: 12px; padding: 20px; }
+
+@media (max-width: 768px) {
+  .table-card {
+    padding: 12px;
+    border-radius: 8px;
+  }
+
+  :deep(.el-table) {
+    font-size: 12px;
+
+    .el-table__cell {
+      padding: 8px 4px;
+    }
+
+    .el-table__header th {
+      padding: 8px 4px;
+    }
+  }
+
+  :deep(.el-button) {
+    padding: 4px 8px;
+    font-size: 12px;
+  }
+}
 </style>