feat(performance): add ISR and Cloudflare cache headers

- Add revalidate=3600 to homepage and products page (1hr ISR)
- Add middleware to set cache headers for HTML pages
- Bypass cache for checkout and cart pages

src/app/[locale]/products/page.tsx

@@ -9,6 +9,8 @@ import { isValidLocale, DEFAULT_LOCALE, getSaleorLocale, type Locale } from "@/l
 import { getPageKeywords } from "@/lib/seo/keywords";
 import { Metadata } from "next";
 
+export const revalidate = 3600;
+
 const baseUrl = process.env.NEXT_PUBLIC_SITE_URL || "https://manoonoils.com";
 
 interface ProductsPageProps {