feat(orderConfirm): 优化订单确认页面功能和样式

- 添加优惠券选择功能
- 增加商品数量选择
- 完善订单信息展示
- 优化支付流程
- 添加错误状态和加载状态处理
- 新增 OrderConfirmSkeleton 组件用于加载骨架屏

src/components/CouponList.tsx

@@ -0,0 +1,96 @@
+import React from 'react'
+import { View, ScrollView } from '@tarojs/components'
+import CouponCard, { CouponCardProps } from './CouponCard'
+import './CouponCard.scss'
+
+export interface CouponListProps {
+  /** 优惠券列表数据 */
+  coupons: CouponCardProps[]
+  /** 列表标题 */
+  title?: string
+  /** 布局方式：vertical-垂直布局 horizontal-水平滚动 */
+  layout?: 'vertical' | 'horizontal'
+  /** 是否显示空状态 */
+  showEmpty?: boolean
+  /** 空状态文案 */
+  emptyText?: string
+  /** 优惠券点击事件 */
+  onCouponClick?: (coupon: CouponCardProps, index: number) => void
+}
+
+const CouponList: React.FC<CouponListProps> = ({
+  coupons = [],
+  title,
+  layout = 'vertical',
+  showEmpty = true,
+  emptyText = '暂无优惠券',
+  onCouponClick
+}) => {
+  const handleCouponClick = (coupon: CouponCardProps, index: number) => {
+    onCouponClick?.(coupon, index)
+  }
+
+  // 垂直布局
+  if (layout === 'vertical') {
+    return (
+      <View className="coupon-list">
+        {title && (
+          <View className="coupon-list__title">{title}</View>
+        )}
+        
+        {coupons.length === 0 ? (
+          showEmpty && (
+            <View className="coupon-list__empty">
+              {emptyText}
+            </View>
+          )
+        ) : (
+          coupons.map((coupon, index) => (
+            <View
+              key={index}
+              onClick={() => handleCouponClick(coupon, index)}
+            >
+              <CouponCard {...coupon} />
+            </View>
+          ))
+        )}
+      </View>
+    )
+  }
+
+  // 水平滚动布局
+  return (
+    <View>
+      {title && (
+        <View className="coupon-list__title" style={{ paddingLeft: '16px' }}>
+          {title}
+        </View>
+      )}
+      
+      {coupons.length === 0 ? (
+        showEmpty && (
+          <View className="coupon-list__empty">
+            {emptyText}
+          </View>
+        )
+      ) : (
+        <ScrollView
+          scrollX
+          className="coupon-scroll"
+          showScrollbar={false}
+        >
+          {coupons.map((coupon, index) => (
+            <View
+              key={index}
+              onClick={() => handleCouponClick(coupon, index)}
+            >
+              <CouponCard {...coupon} />
+            </View>
+          ))}
+        </ScrollView>
+      )}
+    </View>
+  )
+}
+
+export default CouponList