A small AI helper computing how well a value matches a preferred optimum: a
Gaussian bell in [0,1], 1 at the optimum, e^-0.5 one tolerance away, over an
arbitrary input scale (unlike ResponseCurve's monotonic [0,1] shaping). The
building block for environment-suitability growth. Covered by tests.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
