Get Payment Request

curl --request POST \
  --url https:api.markdown2pdf.ai/v1/document/l402/markdown/payment-request \
  --header 'Content-Type: application/json' \
  --data '{
  "offer_id": "offer_12345",
  "payment_methods": "lightning",
  "payment_context_token": "context_token_12345"
}'

{
  "version": "0.2.2",
  "payment_request": {
    "payment_request": "lnbc1..."
  },
  "expires_at": "2025-06-06T14:39:01.055952Z"
}