Modernize project with tooling and PHP 8.2+ refactor

[philippedev101]

This overhauls the entire library to bring it up to modern PHP standards.

• The project now follows the PSR-4 standard, with all code moved to a top-level src/ directory and tests in tests/.
• All dependencies were updated. The library now requires PHP 8.2+, Doctrine Lexer 3.0, Doctrine Collections 2.3, and Symfony String 7.3.
• The core parser and generator logic was rewritten to use strict types, match expressions, and other modern PHP features. The code is simpler and easier to follow now.
• A full set of development tools was added:
  • A GitHub Actions workflow for continuous integration.
  • PHPStan for static analysis.
  • PHP-CS-Fixer for a consistent code style.
• The random number generators were simplified, removing the old and insecure ones in favor of a clear MersenneRandom class.
• The project is now set to version 1.0.0 to mark this as the first stable, modern release.