Replaced `NEXT_PUBLIC_APP_URL` with `APP_URL` in the payment processing logic to ensure proper runtime access. Updated related documentation to clarify the distinction between build-time and runtime environment variables, emphasizing the importance of using `APP_URL` for callback and webhook URLs. Adjusted references in the codebase to reflect this change, enhancing clarity and functionality in the payment flow.
Refactored the iyzico payment integration to improve the handling of payment callbacks and order status updates. Added signature validation for responses to ensure data integrity. Enhanced the `initializeCheckoutForm` function to include buyer's name and surname, and updated the order schema to enforce unique constraints on iyzico tokens. Improved error handling and logging for payment processing, ensuring better tracking of payment states and issues. Updated the app database to reflect these changes.