OpenSSF Best Practices readiness

Summary

This release improves project documentation, security reporting, and development tooling to meet OpenSSF Best Practices Badge requirements.

Documentation

• Added CONTRIBUTING.md with coding standards, test policy, and PR checklist
• Added SECURITY.md with private vulnerability reporting and crypto practices
• Added docs/API.md, docs/CLI.md, and docs/SERVICES.md for external interfaces
• Expanded README.md with problem statement, obtaining the software, basic usage, build/test commands, and security do/don't guidance
• Added English GitHub issue templates for bugs and feature requests

Development

• Added pint.json and Composer scripts: composer test, composer lint, composer lint:fix
• Applied Laravel Pint style fixes across the codebase (PSR-12)

Verification

composer lint   # 241 files pass
composer test   # 69 tests pass