Port the OscilloscopeDisplay from mcltspice docs — Web Audio API
renders stereo audio as Lissajous patterns on a canvas with teal
phosphor persistence. 6 tracks from Jerobeam Fenderson, volume
knob, skin switcher (465/545A), and the Outer Limits easter egg.
Audio: CC BY-NC-SA 4.0, oscilloscopemusic.com
Visual: Nick Watton (codepen.io/2Mogs), rsp2k
