CI: speedup and better coverage

[ThomasWaldmann]

the macOS runner is just too slow - removed from PR jobs.

added pyfuse3 testing to PRs to improve coverage.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.41%. Comparing base (93cd407) to head (fc40be5).
⚠️ Report is 8 commits behind head on master.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #9453      +/-   ##
==========================================
+ Coverage   77.13%   83.41%   +6.28%     
==========================================
  Files          86       86              
  Lines       15327    15329       +2     
  Branches     2275     2275              
==========================================
+ Hits        11822    12787     +965     
+ Misses       2832     1801    -1031     
- Partials      673      741      +68     

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