FluentCart cart and checkout

Keep the browser declarative: it may request an item, quantity, coupon, address, and method, but the server must resolve every price and eligibility decision.

Read checkout-contract.md before adding a custom item, fee, checkout field, or nonstandard client.

Use the actual transport

In Free 1.6.0 normal cart mutations use authenticated-by-nonce admin AJAX:

• action=fluent_cart_checkout_routes plus fc_checkout_action
• action=fluent_cart_place_order for order placement

The X-WP-Nonce header is accepted for action fluentcart or wp_rest. It provides CSRF intent, not user identity or object ownership. Anonymous checkout remains public.