Remove mapping for 'src' to 'auto-mix-prep'

[XanthanGum]

📝 Summary

Remove package mapping 'src' to an unmaintained package 'auto-mix-prep'.
Package is available on pypi, however link to repository is broken.

src is commonly used as a python module folder, and users trying to import their own modules instead under src.X raise a module not not found error, pointing to auto-mix-prep, and are prompted to install with UV.

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✅ Merge Checklist

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• Documentation has been updated where applicable, including docstrings for API changes.
• Tests have been added for the changes made.

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Project	Deployment	Actions	Updated (UTC)
marimo-docs	Ready	Preview, Comment	May 29, 2026 1:54pm

[XanthanGum]

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