Render the header and footer from the root layout

Every page was importing Header and Footer and repeating the same store
name, logo, copyright and nav links. Hoisting both into the root layout
renders them once, and a new config/site.ts holds the values they shared.

The body becomes a flex column so the footer sits at the bottom of short
pages. not-found and error now render inside that chrome, so their
full-viewport centering drops to 60vh.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01D1vsTA4MX6qFd7nqSAKtdV

app/products/[handle]/page.tsx

@@ -1,25 +1,11 @@
-import Header from '@/components/shopify/header';
-import Footer from '@/components/shopify/footer';
 import ProductDetail from '@/components/shopify/product-detail';
 import ProductRecommendations from '@/components/shopify/product-recommendations';
 
 export default function Page() {
   return (
     <>
-      <Header
-        storeName="Shop"
-        logoUrl=""
-        links={[
-          { label: 'Products', url: '/' },
-          { label: 'Collections', url: '/collections' },
-        ]}
-      />
       <ProductDetail addToCartLabel="Add to Cart" />
       <ProductRecommendations title="You May Also Like" />
-      <Footer
-        storeName="Shop"
-        copyright="© 2026 Shop. All rights reserved."
-      />
     </>
   );
 }