export type FormatDateTimeOptions = Intl.DateTimeFormatOptions & {
    emptyValue?: string;
    invalidValue?: string;
    locale?: Intl.LocalesArgument;
};
/**
 * Formats dates for workspace cards, tables, and email history.
 *
 * Accepts `Date`, epoch numbers, and parseable strings. Null/blank values
 * become `emptyValue` (default `"-"`). Invalid dates return `invalidValue`
 * when set, otherwise the original string or `emptyValue`.
 *
 * @example
 * formatDateTime("2026-07-20T12:00:00Z")
 * formatDateTime(null, { emptyValue: "—" })
 */
export declare function formatDateTime(value: unknown, options?: FormatDateTimeOptions): string;