chore: Bump to php 8.4 and upgrade Pest

[tymondesigns]

This pull request updates the package to require PHP 8.4+, modernizes the development toolchain, and improves test and documentation consistency. It removes support for PHP 8.3, updates dependencies and CI configuration, and refactors tests and documentation for clarity and alignment with current best practices.

PHP version and dependency updates:

• Require PHP 8.4+ throughout the codebase, including composer.json, documentation, and CI workflows. This removes support for PHP 8.3 and ensures consistency in requirements. [1] [2] [3] [4] [5] [6]
• Update development dependencies to latest major versions (e.g., Pest 5.x, Pest plugins, symplify/easy-coding-standard), and add Pest PHPStan integration. [1] [2]

Tooling and configuration improvements:

• Update code style and static analysis configurations to target PHP 8.4 and include new Pest and Rector sets. [1] [2] [3] [4]
• Run tests in parallel by default via the composer test script.

Testing improvements:

• Refactor tests to use more expressive, chained expectations for improved readability and maintainability. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14]
• Update Pest test bootstrap to use the new Pest 5.x API.

Documentation consistency:

• Update all code examples in documentation to use direct instantiation of JsonRepairer (i.e., new JsonRepairer(...) instead of (new JsonRepairer(...))) for clarity and consistency. [1] [2] [3] [4] [5]

Bug fix:

• Fix a logic bug in removeComments to correctly detect the end of multi-line comments.