* feat(engine): encoders cap peak bitrate and place keyframes on a set interval
* style(engine): shorten the rate-cap comment
* style(engine): drop the doc lines the comment ratchet flagged
* feat(producer): mp4 renders honour a keyframe interval and a peak bitrate cap on every encoder path
* style(producer): shorten the delivery encoder file headers
* style(producer): drop a comment line from the segment manifest
* style(producer): shorten the integration test header
* test: delivery encoder tests follow the ffprobe argv contract and run in the integration lane
* feat: the render request, server and Lambda plan carry the keyframe interval and peak bitrate cap
* fix(studio): the Studio render route passes the keyframe interval and bitrate cap to the encoder
* chore(studio-server): drop a comment the helper's name already says
* feat(cli): render and lambda render take --keyframe-interval, --max-bitrate and --buffer-size