Exposes a sigma_max input (default 1.0) that scales the entire
schedule by a scalar after all other processing. The curve's natural
peak is 1.0 at the first step, so sigma_max becomes the new starting
sigma and every value scales proportionally; the trailing 0 is
preserved. Default 1.0 is an exact no-op, keeping existing graphs
unchanged.
Applied after the stretch block so it doesn't perturb the
[terminal, 1] remapping math, which assumes a [0, 1] range.
Also documents the parameter in the README with an xychart-beta
diagram comparing 1.0 / 0.75 / 0.5, and adds it to the inputs table.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
