/**
 * First unused `<name>-rN.<ext>` for a path that already exists.
 *
 * Renders are iterative and the EDL is the whole creative decision, so
 * overwriting silently destroys the previous cut. A fresh filename also means
 * a video player opens a genuinely new file rather than a cached old one.
 */
export declare function nextFreeRevision(filePath: string): string;