/**
 * Builds a timestamp-prefixed filename for a locally-saved screenshot.
 *
 * Format: `YYYYMMDDTHHmmssSSS-{id}.png`
 * Compact ISO-8601-ish, no colons (file-safe on all OSes), millisecond
 * precision, lexicographically sortable.
 */
export declare function formatScreenshotFilename(timestamp: number, id: string): string;
