Retake turns demo recordings into rerunnable files

Field notes

Retake represents a walkthrough as a YAML file containing the interaction intent, selectors, and waits, then checks that flow before capturing the browser session. Each run produces an MP4, scene stills, and a proof log, while captions and camera framing can be revised after recording. The homepage illustrates the maintenance model with a renamed checkout button: one selector changes, and the same flow can be run again rather than recreated by hand.