- Updated `phpunit.php` to improve code style.
- Modified `phpunit.xml` to align with PHPUnit 12.3 schema and updated source filtering.
- Introduced `pint.json` for code style configuration.
- Changed return types in `EncoderInterface` and `OptionsInterface` to use `self` instead of `EncoderInterface` and `OptionsInterface`.
- Updated various classes to improve code style and consistency, including constructor and method definitions.
- Simplified exception classes by using `use Exception` syntax.
- Added initial tests using Pest framework, including example test and test case structure.
- Refactored existing tests to follow a consistent naming convention and improved setup methods.

…tattributes

…ed ExampleTest

… Validator class

…with Pint