refactor: rename shopLayoutData to storefrontLayoutData

Align Alpine.js base component naming with storefront terminology.
Updated across all storefront JS, templates, and documentation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/modules/cart/templates/cart/storefront/cart.html

@@ -175,7 +175,7 @@
 <script>
 document.addEventListener('alpine:init', () => {
     Alpine.data('shoppingCart', () => {
-        const baseData = shopLayoutData();
+        const baseData = storefrontLayoutData();
 
         return {
             ...baseData,