docs : add EXAMPLE.md with practical usage scenarios

[Sohaan24]

This PR introduces a new EXAMPLES.md file to help new developers get started quickly with the react-infinite-scroll-hook, as requested in the issue.

Changes Made

Added 3 real-world, copy-pasteable examples tailored to the hook's specific API:

1. Standard Feed: Attaching the ref to the last item in a list.
2. Image Grid / Masonry Layout: Using a bottom boundary/sentry element.
3. Chat Application: Implementing a reverse infinite scroll using flex-direction: column-reverse and a top boundary.

Type of change

📚 Documentation update

Checklist

• I have read the README.md and ensured the examples match the current API structure.
• The markdown formatting is clean and renders correctly.

Thank you for the opportunity to contribute to the Stackaura ecosystem! 🚀