Interface GenericPaymentMessage

EIP-712 message payload for a generic op payment.

• opType is "grant" for legacy grant lifecycle payments or "data_access" for a standalone receipt-bound read.
• opId is the bytes32 id of the operation being paid for: the grant id for "grant", or accessRecord.recordId for "data_access".
• asset is the ERC-20 token address, or the zero address for native VANA.
• amount is the total amount in base units (wei for VANA). Must match the sum the gateway expects for the current lifecycle of the op.
• paymentNonce must be a positive integer unique per payerAddress. Use 1 for the first payment; increment by at least 1 for each subsequent call.