Create Payment Session

curl --request POST \
  --url https://api.authsignal.com/v1/terminal/payment-session \
  --header 'Content-Type: application/json' \
  --data '{
  "amount": 123,
  "reference": "<string>",
  "currency": "<string>"
}'

{
  "challengeId": "ef6b3212-6121-4a9e-92ef-09d819e36e93",
  "status": "PENDING",
  "reference": "xxx-xxx-xxx"
}