Added Real-World Examples for State and Memento Patterns (PRs submitted)

Hi everyone 👋

I've noticed that the the https://github.com/RefactoringGuru/design-patterns-php repo is missing real world examples for State & Memento patterns. So I’ve submitted two pull requests:

• ✅ Add RealWorld example for the State pattern

• ✅ Add RealWorld example for the Memento pattern

Both examples are written with readability and practical use cases in mind, consistent with the repo's style. I’d love for the maintainers and community to take a look, give feedback, or consider merging them if they meet the standards.

I also want to express my sincere gratitude to the author of Refactoring Guru — the content has been incredibly helpful in deepening my understanding of design patterns. It's a fantastic resource for developers at all levels. Thank you for making this knowledge so accessible!

Looking forward to contributing more!

Thanks 🙏
Driss