Add sky-cam-frigate service using Frigate exports for timelapse source

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).

setup.sh

@@ -87,6 +87,7 @@ is_installed() {
         silent-send) [ -d "$ACTUAL_HOME/silent-send/.git" ] ;;
         sync-cc) [ -f "$ACTUAL_HOME/sync-cc/sync_cc.py" ] ;;
         sky-cam) [ -d "$ACTUAL_HOME/sky-cam/.git" ] ;;
+        sky-cam-frigate) [ -d "$ACTUAL_HOME/sky-cam/.git" ] && [ -f "$ACTUAL_HOME/sky-cam/frigate-retime.sh" ] ;;
         *) [ -e "$DOCKER_DIR/$1" ] ;;
     esac
 }