/**
 * Return the current second using the system timeZone.
 *
 * - Uses Temporal.Now.plainDateTimeISO to get current second in system timezone.
 * - Returns zero-padded string (e.g., "45").
 * - Returns "" when system timezone is unavailable.
 *
 * @returns current second string (zero-padded) or "" on invalid
 *
 * @example getSecond() // "00"
 * @example getSecond() // "" (when system timeZone unavailable)
 */
export declare function getSecond(): string;