/**
 * Formats a Date as a human-readable relative time string.
 *
 * @plan PLAN-20260214-SESSIONBROWSER.P03, PLAN-20260214-SESSIONBROWSER.P05
 * @requirement REQ-RT-001, REQ-RT-002, REQ-RT-003, REQ-RT-004
 * @pseudocode integration-wiring.md lines 170-212
 */
export declare function formatRelativeTime(date: Date, options?: {
    mode?: 'long' | 'short';
    now?: Date;
}): string;
