/**
 * Parses a heterogeneous date input (Date, ISO string, locale-formatted string, or epoch number)
 * into a `Date`. Returns `undefined` when the input is empty or unparseable.
 */
export declare function parseToDate(v: Date | string | number | undefined, locale: string): Date | undefined;
/** Formats a `Date` as a canonical `YYYY-MM-DD` ISO date string, or `""` when undefined. */
export declare function formatToInputString(d: Date | undefined): string;
/** Returns the epoch millis at the start of `d`'s local calendar day. */
export declare function startOfDayMs(d: Date): number;
/** Clamp a date to `[minDate, maxDate]`; returns the same date if in range or no bounds. */
export declare function clampToRange(date: Date | null | undefined, minDate: Date | undefined, maxDate: Date | undefined): Date | null;