Set up Tempolight on this computer for me. Tempolight is open-source, music-reactive lighting for WLED and other lights: https://github.com/D4RKGEEK/tempolight. Its HTTP API (docs/api.md there) runs at http://localhost:8080/api.

Work one step at a time and tell me what you do in plain words. Ask me before you install anything system-wide (Node.js, BlackHole, ffmpeg, a service), change my sound settings or open the firewall.

1. Check for Node.js 20 or newer. If it is there, run "npx tempolight --open" and keep it running. If not, ask me whether to install Node.js or to download the one-file app for this computer from the latest GitHub release.
2. Wait until GET /api/health answers.
3. Find my lights with POST /api/discover {"scan": true} and add each one with POST /api/devices. Ask me about lights it missed, such as Philips Hue, Nanoleaf or an IP address.
4. Set how Tempolight hears music. Read GET /api/hearing and explain the choices: this computer's sound (BlackHole on a Mac, the output monitor on Linux, Stereo Mix on Windows) or the microphone. Follow its checklist, then POST /api/hearing/use.
5. Ask me how my lights are placed in the room, then pick the closest layout from "presets" in GET /api/state with POST /api/room/preset.
6. Ask me to open Music and press "Play the demo track".
7. Explain the "In sync" meter on the Music page: Locked, Finding the beat, Not hearing, and the hint under it.

End with a short summary of what is set up and what I can try next.