Refactor: Move package behind src/

[BradyAJohnston]

Moves the package behind src and fixes build tools for use with uv. Tweaks some metadata in docs to emit llms.txt as well.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.40%. Comparing base (0f839b8) to head (8e0b67c).

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #71   +/-   ##
=======================================
  Coverage   90.40%   90.40%           
=======================================
  Files          13       13           
  Lines         792      792           
=======================================
  Hits          716      716           
  Misses         76       76           

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