These instructions are accurate to your codebase
Every step maps 1-to-1 with the actual CryptoCheckout files: the PHP plugin (class-ccg-gateway.php), HMAC auth (lib/hmac.ts), session API (/api/v1/checkout/sessions), MoonPay webhook route (/api/v1/webhooks/moonpay), and Supabase stores/sessions/webhook_events tables.