/**
 * Solana X402 payment signing.
 *
 * Builds a SPL TransferChecked instruction, signs via wallet adapter,
 * and produces the X-Payment header.
 */
import type { PaymentRequirement, SolanaWalletAdapter, X402PaymentEnvelope } from './types.js';
export declare function signSolanaPayment(requirements: PaymentRequirement, wallet: SolanaWalletAdapter): Promise<X402PaymentEnvelope>;