feat: integrate SEO system into pages

- Add OrganizationSchema to root layout
- Add ProductSchema with metadata to product pages
- Add enhanced metadata to homepage with keywords
- Add enhanced metadata to products listing page
- Add noindex to checkout page via layout
- Implement canonical URLs, OpenGraph, and Twitter cards

src/app/[locale]/checkout/layout.tsx

@@ -0,0 +1,26 @@
+import type { Metadata } from "next";
+import { getPageKeywords } from "@/lib/seo/keywords";
+import { isValidLocale, DEFAULT_LOCALE } from "@/lib/i18n/locales";
+
+export async function generateMetadata({ params }: { params: Promise<{ locale: string }> }): Promise<Metadata> {
+  const { locale } = await params;
+  const validLocale = isValidLocale(locale) ? locale : DEFAULT_LOCALE;
+  const keywords = getPageKeywords(validLocale, 'checkout');
+  
+  return {
+    title: keywords.metaTitle,
+    description: keywords.metaDescription,
+    robots: {
+      index: false,
+      follow: false,
+    },
+  };
+}
+
+export default function CheckoutLayout({
+  children,
+}: {
+  children: React.ReactNode;
+}) {
+  return children;
+}