feat: implement header/footer visibility controls for checkout and thankyou pages

- Created LayoutWrapper component to conditionally render header/footer based on route
- Created MinimalHeader component (logo only)
- Created MinimalFooter component (trust badges + policy links)
- Created usePageVisibility hook to get visibility settings per page
- Wrapped ClassicLayout with LayoutWrapper for conditional rendering
- Header/footer visibility now controlled directly in React SPA
- Settings: show/minimal/hide for both header and footer
- Background color support for checkout and thankyou pages

customer-spa/src/lib/cart/store.ts

@@ -10,6 +10,8 @@ export interface CartItem {
   price: number;
   image?: string;
   attributes?: Record<string, string>;
+  virtual?: boolean;
+  downloadable?: boolean;
 }
 
 export interface Cart {