Fix gamut mapping binary search - #1323
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Fixes #1298.
The gamut mapping binary search returned as soon as it found a chroma under the JND. The spec keeps searching upward from that point and returns the largest chroma still under the JND. Because of the early return, sRGB fallbacks for wide gamut colors came out less saturated than the spec and colorjs.io produce.
This change follows the spec pseudocode: it clips the origin color once before the loop, carries the
min_inGamutflag, and returns the last clipped color. The epsilon now matches the spec value and the spec link points to the current anchor.The same search is implemented in colordx, where it matches colorjs.io on a large set of out of gamut samples. The loop here mirrors that math.
Test expectations that depended on the old behavior are updated, and the cases from the issue are added. All new values match colorjs.io with
method: "css".