Chart.h draws Diagnostics > History, the noise sweep and the trail's height
profile: round values up the left, labels along the bottom, a solid fill
(no transparency) and, under a finger, the sample's value and when / where.
Sim: sim_open("histdemo") / ("profdemo") fill them with made-up data.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
