curl --request POST \
  --url {protocol}://{host}/wp-json/cocart/preview/checkout/payment-context \
  --header 'Content-Type: application/json' \
  --data '{
  "payment_method": "<string>"
}'

{
  "gateway_id": "stripe",
  "title": "Credit Card (Stripe)",
  "cart_total": "44.98",
  "currency": "USD",
  "client_secret": "pi_abc123_secret_xyz789",
  "payment_intent_id": "pi_abc123",
  "public_key": "pk_test_abc123xyz789"
}