Smoke test
Runner smoke test.
The brief
Build a tiny page that shows the word "Prism" over a slowly rotating CSS rainbow gradient, and generate one small resource file for it yourself: a 1-second 440 Hz sine tone as ./site/beep.wav (made with a script) that plays when the word is clicked. Keep it very small and finish within 3 minutes: run the check once, then write NOTES.md.