A saturating add is five instructions where a wrapping one is one, and
it has no i32 vector form. Measured on the fixed-shape fixture, seed 1,
depth 8, 500 frames of `many`: 2,098M instructions and ~826M cycles down
to 1,918M and ~771M, with `random`, `tabs` and `text` byte-identical at
1920x1200 and the 100-seed oracle passing.
What saturating bought was ordering past the end of the range, where a
layout is already a defect; wrapping makes that defect obvious instead
of plausible. `from_f32` still clamps, since a float has the range to
come from anywhere, and `narrow` stays for `Holds`, whose range past
i32 really does mean unbounded. MIN and MAX remain unbounded ends only
where they are compared and never added to, which is every use.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>