Storefront web components

Component	Responsibility
App Router pages	Render catalog, product detail, cart, checkout, and order confirmation routes.
Cart provider	Keep browser-local quantities and totals synchronized for the current shopper.
Catalog adapter	Read the trusted local catalog through the catalog package.
Checkout panel	Submit create/capture requests and expose loading, failure, and success states.

The browser never receives the PayPal client secret. Payment calls cross the server route-handler boundary described in PayPal BFF components.