Replace the in-tree Wyman analytic CIE fit with a repository CIE 1931
2-degree LUT derived from the 360-830 nm, 1 nm-linear CSV reference. The
GRBBLUT3 table stores 1024 uniform log(T) XYZ nodes over
[670.146556, 101408.88] K with four-point cubic Lagrange interpolation, and
the same CSV reference supplies a three-term Rayleigh-Jeans form above the
table and an inverse-temperature/log-XYZ crossover with channel-specific
endpoint forms below it. The loader validates the header and payload
checksum and rejects legacy formats and runtime generation.
Initialize the backend in the renderer, frame test, and PSF capture tool so
the new default is active wherever colors are produced.
Check spherical area weight sums against a fixed 1e-8 tolerance and normalize accepted weights before interpolation. Skip invalid images in both catalog paths.
Add a thin-triangle regression for both parities, document the measured tolerance margin, and refresh HDR fixtures with strict comparisons restored.
wyj