fix: resolve email shortcode rendering and TypeScript errors

- Fix EmailRenderer.php: add missing \ namespace prefix on instanceof
  checks for WC_Order, WC_Product, WC_Customer in get_variables()
  (root cause of unrendered {order_number} etc. in all order emails)
- Fix ProductCard.tsx: remove deprecated isClassic/isModern/isBoutique
  branches, consolidate into single settings-driven render path
- Fix AccountLayout.tsx: add missing return statement
- Remove orphaned Layout.tsx (imported nothing, referenced missing Header)

customer-spa/src/pages/Account/components/AccountLayout.tsx

@@ -201,7 +201,8 @@ export function AccountLayout({ children }: AccountLayoutProps) {
   );
 
   // Responsive layout: Tabs on mobile, Sidebar on desktop
-  <div className="py-8">
+  return (
+    <div className="py-8">
     {/* Mobile: Tab Navigation */}
     {renderTabNav()}
 
@@ -216,6 +217,7 @@ export function AccountLayout({ children }: AccountLayoutProps) {
         </div>
       </div>
     </div>
-  </div>
+    </div>
+  );
 }