refactor: Modernize and optimize check_structure.py script

[geniruphin-junior]

Description

This Pull Request modernizes and optimizes the check_structure.py script by leveraging modern Python 3.10+ practices, improving memory consumption, and enforcing clean code standards.

Changes Made

• Architecture: Encapsulated the execution logic inside a proper main() function instead of running it raw under the __main__ block.
• Memory Optimization: Converted _find_misplaced_java_files to return an Iterator (generator expression) instead of building a full list in memory, which scales better as the repository grows.
• Clean Code & Readability:
  • Simplified the parent directory lookup by using java_file.parents directly.
  • Used any() for a cleaner and more idiomatic path validation logic.
  • Extracted hardcoded paths into a tuple constant (VALID_PATHS).
• CI/CD Best Practices: Redirected error outputs to sys.stderr instead of standard stdout, and added clear visual feedback (❌ / ✅) with file counters for better logs readability.

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• The script runs without any bugs or regressions

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.24%. Comparing base (fd2858e) to head (03af606).
⚠️ Report is 27 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #7521      +/-   ##
============================================
- Coverage     80.25%   80.24%   -0.01%     
+ Complexity     7358     7357       -1     
============================================
  Files           810      810              
  Lines         23787    23787              
  Branches       4678     4678              
============================================
- Hits          19091    19089       -2     
  Misses         3940     3940              
- Partials        756      758       +2     

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[prashantpiyush1111]

Nice refactor overall. One suggestion: could you keep the inline comments and docstrings in English for consistency with the rest of the repository? The implementation looks good, but using a single language throughout the codebase makes maintenance easier.

[DenizAltunkapan]

i agree with @prashantpiyush1111

[github-actions]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contribution!

[github-actions]

Please reopen this pull request once you have made the required changes. If you need help, feel free to ask in our Discord server or ping one of the maintainers here. Thank you for your contribution!