feat: galilean rotation

[nstarman]

This is a single rotation, not a time-dependent rotation.

[codecov]

Codecov Report

Attention: Patch coverage is 91.66667% with 5 lines in your changes are missing coverage. Please review.

Project coverage is 88.72%. Comparing base (c972652) to head (34f33bb).
Report is 37 commits behind head on main.

Files	Patch %	Lines
src/galax/coordinates/operators/galilean.py	90.56%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #171      +/-   ##
==========================================
+ Coverage   88.44%   88.72%   +0.27%     
==========================================
  Files          42       54      +12     
  Lines        1324     1782     +458     
==========================================
+ Hits         1171     1581     +410     
- Misses        153      201      +48     

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