CI - add ruff check of the code

[pavoljuhas]

• Add minimum ruff tool configuration to pyproject.toml
• CI - add ruff to the "Lint check" CI job

Partially implements #7371

[pavoljuhas]

Verifying output as colorized at https://github.com/quantumlib/Cirq/actions/runs/15221472630/job/42817712311?pr=7372#step:6:11

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.68%. Comparing base (1c0ba5b) to head (c5b29a9).
Report is 8 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7372      +/-   ##
==========================================
- Coverage   98.68%   98.68%   -0.01%     
==========================================
  Files        1112     1112              
  Lines       97585    97641      +56     
==========================================
+ Hits        96303    96357      +54     
- Misses       1282     1284       +2     

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[mhucka]

Totally optional: perhaps this file should be renamed to something like lint.env.txt or lint-tools.env.txt, to be more in line with the contents and ci.yml?

[pavoljuhas]

sure, done in c5b29a9

[mhucka]

LGTM with an optional minor and ignorable suggestion.

Thanks for doing this.