Duplicates services/sky-cam.sh into a Frigate-backed variant that pulls
recordings via Frigate's export API instead of a JPEG image folder.
Includes a frigate-retime.sh helper that exports a coarse timelapse,
measures its actual duration with ffprobe, and re-encodes once with a
computed setpts factor to hit an exact target length (e.g. a Four
Seasons movement's runtime).
