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]/page.tsx

@@ -16,6 +16,8 @@ import { getPageKeywords, getBrandKeywords } from "@/lib/seo/keywords";
 import { Metadata } from "next";
 import Image from "next/image";
 
+export const revalidate = 3600;
+
 const baseUrl = process.env.NEXT_PUBLIC_SITE_URL || "https://manoonoils.com";
 
 export async function generateMetadata({ params }: { params: Promise<{ locale: string }> }): Promise<Metadata> {