/**
 * Convert a UTC Instant string to a zoned ISO 8601 datetime string.
 *
 * - Uses Temporal.Instant.from to parse, converts to specified timezone.
 * - Validates both UTC input and timezone.
 * - Returns "" for invalid input.
 *
 * @param value UTC Instant string
 * @param timeZone IANA timeZone identifier
 * @returns zoned ISO 8601 string or "" on invalid
 *
 * @example convertUtcToZoned("2024-02-29T00:00:00Z", "America/New_York") // "2024-02-28T19:00:00-05:00[America/New_York]"
 * @example convertUtcToZoned("invalid", "UTC") // ""
 */
export declare function convertUtcToZoned(value: string, timeZone: string): string;