Interface GenericPaymentMessage

EIP-712 message payload for a generic op payment.

• opType is currently "grant". Additional types (file, builder, schema) may be added in future protocol versions.
• opId is the bytes32 id of the operation being paid for (e.g. grantId).
• 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.