chore(ci): Setup Python with uv

[effigies]

I noticed that the OSX runs were using Python 3.14 for all runs. Maybe setting up Python with uv will fix this.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.95%. Comparing base (3a0ce09) to head (588bf73).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #47   +/-   ##
=======================================
  Coverage   90.95%   90.95%           
=======================================
  Files          12       12           
  Lines         774      774           
  Branches      116      116           
=======================================
  Hits          704      704           
  Misses         46       46           
  Partials       24       24           

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