refactor(catalog): 废弃 LEWAN_ 镜像，统一英文 SKU 与积分价，商品图按 SKU 缓存

对外目录只保留英文主 sku；迁移硬删镜像并校准 1元=100积分；发货页/凭证优先使用 local {sku}.webp。

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/utils/voucher.ts

@@ -89,12 +89,12 @@ export async function generateDeliveryVoucher(order: DeliveryOrderInfo): Promise
   ctx.lineWidth = 1
   strokeRoundRect(ctx, cardX + 40, prodCardY, cardW - 80, prodCardH, 16)
 
-  // 尝试加载商品图片（优先命中本地下载缓存）
+  // 尝试加载商品图片（优先 SKU 本地缓存）
   let productImgLoaded = false
-  if (order.product?.image) {
+  const productImgURL = resolveProductImage({ sku: order.product?.sku, url: order.product?.image })
+  if (productImgURL) {
     try {
-      const imgURL = resolveProductImage(order.product.image)
-      const img = await loadImage(imgURL)
+      const img = await loadImage(productImgURL)
       const imgSize = 146
       const imgX = cardX + 64
       const imgY = prodCardY + 32