Migrate product data from Kirby to Shopify Storefront API

- Add product loaders (product-loader.js, products-list-loader.js) to fetch data from Shopify
- Extend Shopify API client with getProductByHandle() and getAllProducts() methods
- Integrate Shopify metafields for multilingual support (custom.title_en, custom.description_en)
- Refactor product.php and home.php templates to load content dynamically
- Simplify product blueprint to minimal routing configuration
- Create generic buy-button.php snippet with variant selection
- Update footer.php with conditional script loading
- Refactor _section--product.scss for better Sass structure
- Add translations for loading states and product errors
- Clean up old Kirby product content files

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

site/languages/en.php

@@ -27,6 +27,9 @@ return [
         'addedToCart' => 'Added! ✓',
         'errorAddToCart' => 'Error - Try again',
         'closeCart' => 'Close cart',
+        'loading' => 'Loading...',
+        'productNotFound' => 'Product not found',
+        'selectVariant' => 'Select',
 
         // Blueprints - Home
         'home.title' => 'Home',