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/core/static/storefront/js/storefront-layout.js

@@ -16,7 +16,7 @@ const shopLog = {
  * Shop Layout Data
  * Base Alpine.js component for shop pages
  */
-function shopLayoutData() {
+function storefrontLayoutData() {
     return {
         // Theme state
         dark: localStorage.getItem('shop-theme') === 'dark',
@@ -243,7 +243,7 @@ function shopLayoutData() {
 }
 
 // Make available globally
-window.shopLayoutData = shopLayoutData;
+window.storefrontLayoutData = storefrontLayoutData;
 
 /**
  * Language Selector Component