/** Calculate age in seconds from an ISO date string. Returns undefined on invalid input. */
export declare function dateToAgeSeconds(dateStr: string | null | undefined): number | undefined;
/** Clamp a result count to [1, maxVal], returning defaultVal when value is absent or NaN. */
export declare function clampNumResults(value: number | undefined, defaultVal: number, maxVal: number): number;
/** UTC `YYYY-MM-DD` lower bound for a relative recency window, for engines that only accept absolute `after` dates. */
export declare function recencyAfterDate(recency: "day" | "week" | "month" | "year"): string;