Discover and restrict available local payment methods per checkout using Adyen's /paymentMethods endpoint

Verified steps

1. POST /paymentMethods with merchantAccount, amount (value + currency), countryCode, and shopperLocale to retrieve the set of payment methods valid for that specific transaction context.
2. Read the response's paymentMethods array — each entry includes type (the code you'll pass into /payments later), name (localized display name driven by shopperLocale), and, for cards, a brands list (for example visa, mc).
3. Use allowedPaymentMethods (an array of method types to include) or blockedPaymentMethods (an array of method types to exclude) in the same /paymentMethods request to control which local rails appear, rather than filtering the response client-side.
4. Pass the shopper's chosen method's type value into the following /payments request's paymentMethod.type field to actually initiate the selected payment.
5. Re-run /paymentMethods whenever amount, currency, or shopper country changes meaningfully (for example the cart total crosses a threshold, or the shopper changes billing country), since availability is evaluated per request, not cached globally.