Baseline Removal

[CatYang3]

Summary

Describe the main changes in this PR:

• Capture the first N samples and calculate the average as the baseline.
• Subsequent samples have the baseline value subtracted
• Baseline is calculated after first initialization and upon reset
• Problem: the test 'raw' data already has baseline removed at the beginning, so this functionality isn't being tested. proposed solution: record new raw data directly from IMUs

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Code Quality Checklist

Before requesting review, ensure:

• All CI/CD pipelines pass
• Code includes docstrings and type hints
• I added new tests where necessary
• I ran make tree to update the README.md

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Additional Notes

• Anything else reviewers should know?
• Attach outputs, plots, logs, or GIFs here.