chore: add pre-commit configuration with Black formatter

[vidonnus]

Add Pre-commit Configuration with Black Formatter

Summary

This PR adds pre-commit hooks to enforce code quality and consistent formatting across the codebase using Black and other automated checks.

Changes

New Files

• .pre-commit-config.yaml - Pre-commit configuration with:
  • Black formatter (88 character line length)
  • Trailing whitespace removal
  • End-of-file newline fixer
  • YAML syntax validation
  • Large file detection
  • Merge conflict detection
  • Line ending normalization (LF)

Documentation Updates

• CONTRIBUTING.md - Added "Code Style and Quality" section with:
  • Pre-commit installation instructions
  • List of automated checks
  • Workflow explanation

Code Formatting

• Applied Black formatting across Python files
• Removed trailing whitespace (22 files)
• Fixed end-of-file newlines
• Normalized spacing and formatting

Benefits

✅ Consistent code style - Black ensures uniform formatting across all Python code
✅ Automated quality checks - Catches common issues before commit
✅ Reduced review friction - No more style debates or manual formatting fixes
✅ Better git diffs - Clean file endings and consistent formatting
✅ Easy onboarding - New contributors get instant feedback on code style

Testing

• All pre-commit hooks pass successfully
• No functional changes to code logic
• Formatting changes are purely cosmetic

Installation for Contributors

pip install pre-commit
pre-commit install

Hooks will run automatically on git commit. To run manually:

pre-commit run --all-files