/**
 * Validate an EVM address for seller / payTo use.
 * - Must be 0x + 40 hex
 * - Mixed-case addresses must pass EIP-55 checksum (viem strict)
 * - Returns checksummed `0x…` form
 *
 * Invalid → throws (callers should hard-fail startup or return 500 config error).
 */
export declare function assertValidAddress(value: string | undefined | null, label?: string): `0x${string}`;
/** Seller alias — same rules as assertValidAddress. */
export declare function assertValidSeller(value: string | undefined | null): `0x${string}`;
export declare function tryParseAddress(value: string | undefined | null): `0x${string}` | undefined;