/**
 * Return true when interval B is fully contained within interval A — every instant of B
 * falls within A.
 *
 * - Uses `Temporal.PlainTime.compare` for comparison.
 * - Equivalent to 4-argument `intervalContainsTime(aStart, aEnd, bStart, bEnd)`.
 * - Returns `false` if either interval is invalid (`start > end`).
 * - Returns `false` on invalid input (wrong type, malformed strings).
 *
 * @param aStart ISO 8601 time string for the outer interval start
 * @param aEnd ISO 8601 time string for the outer interval end
 * @param bStart ISO 8601 time string for the inner interval start
 * @param bEnd ISO 8601 time string for the inner interval end
 * @returns true if B is fully contained in A, or false on invalid input
 *
 * @example intervalEngulfsTime("09:00:00", "17:00:00", "12:00:00", "13:00:00") // true
 * @example intervalEngulfsTime("09:00:00", "17:00:00", "09:00:00", "17:00:00") // true (equal intervals)
 * @example intervalEngulfsTime("09:00:00", "17:00:00", "09:00:00", "12:00:00") // true
 * @example intervalEngulfsTime("12:00:00", "13:00:00", "09:00:00", "17:00:00") // false
 * @example intervalEngulfsTime("invalid", "17:00:00", "12:00:00", "13:00:00") // false
 */
export declare function intervalEngulfsTime(aStart: string, aEnd: string, bStart: string, bEnd: string): boolean;