/**
 * Sort an array of PlainDateTime values in ascending or descending order.
 *
 * - Returns empty array if no valid datetimes.
 * - Validation is performed on each item in the array.
 *
 * @param dateTimes Array of ISO PlainDateTime strings (e.g. "2024-03-10T12:00:00")
 * @param order "asc" for ascending (earliest first) | "desc" for descending (latest first)
 * @returns Sorted array of datetime strings
 *
 * @example sortDateTimes(["2024-03-10T12:00:00", "2024-01-01T08:00:00", "2024-02-15T15:30:00"]) // ["2024-01-01T08:00:00", "2024-02-15T15:30:00", "2024-03-10T12:00:00"]
 * @example sortDateTimes([]) // []
 */
export declare function sortDateTimes(dateTimes: string[], order?: "asc" | "desc"): string[];