Returns the invoice context for a payor payment session.
Provide x-session-token and x-signature headers from the invoice creation response.
Payment session token (opaque). Returned when creating an invoice; send on every request.
Payment session signature in the format signature_hash.timestamp_ms (returned with the invoice/session).
Session details
unpaid, underpaid, paid, expired, canceled Milliseconds until expiration (clamped at 0).
mainnet, devnet