Update pixelmatch-cpp to match the current JavaScript implementation

Hi,

I noticed that pixelmatch-cpp appears to be based on an older version of the JavaScript implementation and is no longer fully aligned with the current pixelmatch.

The current JavaScript version is 7.2.0, while the C++ implementation still appears to use the older YIQ-based color-difference metric. The current JavaScript implementation has since moved to OKLab + HyAB for color comparison.

This raises a couple of questions:

Is there a plan to update pixelmatch-cpp to match the current JavaScript implementation?
Is behavioral compatibility between the C++ and JavaScript implementations a goal?
If so, would it be possible to port the newer color-difference algorithm and other changes from the current JavaScript version?
In particular, it would be useful to have the C++ implementation produce the same diff results as the current JavaScript implementation when given the same images and configuration.

I'm interested in using Pixelmatch from a native C++ application without requiring Node.js, so having a current C++ implementation would be very useful.

Thanks!

将现有的 pixelmatch-cpp 实现与当前的 JavaScript pixelmatch 7.2.0 实现进行比较，首先关注颜色差异度量。确定移植 OKLab + HyAB 及其他更改的范围；对于相同的图像和配置，如果 diff 结果与 JavaScript 的结果一致，则视为完成。