refactor: 将Data到ViewModel的转换由App转移至Server端

- 将逻辑转移到Server端后，简化前端逻辑

server/api/cms/productList.get.ts

@@ -0,0 +1,6 @@
+import { productService } from '~~/server/services/cms/productService';
+export default defineEventHandler(async (event) => {
+  const locale = getHeader(event, 'x-locale') || 'zh-CN';
+
+  return productService.getProductList(locale);
+});