export interface FreshnessMetadata {
    lastReviewedAt?: string;
    reviewCycle?: string;
    expiresAt?: string;
}
export interface AssetFreshnessEvaluation {
    expired: boolean;
    reviewOverdue: boolean;
    expiresAt?: string;
    reviewDueAt?: string;
}
/** Return today's date as a UTC ISO date string for deterministic comparisons. */
export declare function todayIsoDate(now?: Date): string;
/** Validate strict YYYY-MM-DD dates, rejecting impossible calendar dates. */
export declare function isIsoDate(value: string): boolean;
/** Parse the initially supported ISO 8601 day duration subset, such as P90D. */
export declare function parseDayDuration(value: string): number | undefined;
/** Evaluate supported explicit freshness metadata against one ISO date. */
export declare function evaluateAssetFreshness(metadata: FreshnessMetadata, today: string): AssetFreshnessEvaluation;