Rename DartLoader to UrdfParser

[jslee02]

Summary

• rename URDF parser to dart::utils::UrdfParser with deprecated DartLoader alias
• update python bindings/stubs/tests/docs to new UrdfParser naming with aliases
• adjust CI to handle sccache env guard and merge latest main

Testing

• pixi run lint

[codecov]

Codecov Report

❌ Patch coverage is 95.45455% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 61.40%. Comparing base (e1e2f07) to head (ecbb740).
⚠️ Report is 243 commits behind head on main.

Files with missing lines	Patch %	Lines
dart/utils/urdf/UrdfParser.cpp	95.45%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2269      +/-   ##
==========================================
+ Coverage   61.39%   61.40%   +0.01%     
==========================================
  Files         360      360              
  Lines       32623    32622       -1     
  Branches     4281     4282       +1     
==========================================
+ Hits        20029    20033       +4     
+ Misses      12594    12589       -5     

Flag	Coverage Δ
unittests	61.40% <95.45%> (+0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
dart/utils/urdf/UrdfParser.cpp	83.42% <95.45%> (ø)

... and 2 files with indirect coverage changes

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