Add automatic hand scaling factor calibration

[cathyliyuanchen]

Description

Adding auto-calibration of the scaling factor param in retargeter, according to human hand length from the hand poses. The robot pinky curls on its own if the scaling factor is too small, and the index finger have trouble curling if the scaling factor is too large, but "small/large" depend on the hand size.

Type of change

• Bug fix (non-breaking change which fixes an issue)

Screenshots

Before	After

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Checklist

• I have run the pre-commit checks with ./isaaclab.sh --format
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• I have updated the changelog and the corresponding version in the extension's config/extension.toml file
• I have added my name to the CONTRIBUTORS.md or my name already exists there
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[ooctipus]

Thanks for the PR, there is no issue from formatting.

I am a bit concerning that editing so many files to introduce a flag seems a bit extra, I would suggest have one more mimic engineer to take a look and judge what could be the best way to introduce them before merging