feat: 接入预览模式（Next.js Draft Mode）

app/products/[slug]/page.tsx

@@ -1,7 +1,9 @@
 import { notFound } from "next/navigation";
 import type { Metadata } from "next";
 import { getProductBySlug } from "@/services/product.service";
+import { getPreviewOrFallback } from "@/services/preview.service";
 import { BlockRenderer } from "@/blocks/BlockRenderer";
+import type { ProductPageDetail } from "@/types/wagtail";
 
 interface ProductDetailPageProps {
   params: Promise<{ slug: string }>;
@@ -19,7 +21,11 @@ export default async function ProductDetailPage({
   params,
 }: ProductDetailPageProps) {
   const { slug } = await params;
-  const product = await getProductBySlug(slug).catch(() => null);
+  const product = await getPreviewOrFallback<ProductPageDetail>(
+    "products.productpage",
+    "body,summary",
+    () => getProductBySlug(slug).catch(() => null),
+  );
 
   if (!product) {
     notFound();