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/api/index.ts

@@ -71,6 +71,8 @@ export const merchantApi = {
     request.get('/merchant/products', { params }).then((r) => r.data.data as PageResult<MerchantProduct>),
   updateProductStatus: (id: number, status: MerchantProduct['status']) =>
     request.patch(`/merchant/products/${id}/status`, { status }).then((r) => r.data.data),
+  deleteProduct: (id: number) =>
+    request.delete(`/merchant/products/${id}`).then((r) => r.data.data),
   orders: (params?: Record<string, unknown>) =>
     request.get('/merchant/orders', { params }).then((r) => r.data.data as PageResult<FulfillmentOrder>),
   manualOrderProducts: () =>