docs: enhance README with improved contribution guide and social links

[Akash-Adhya]

Description

This PR updates the README.md with:

• Clearer step-by-step contribution guidelines
• Proper formatting and code blocks for setup instructions
• Official Keploy social links (LinkedIn, YouTube, Twitter)
• A polished and welcoming tone for new contributors

Type of change

• Documentation update (improvement in README)

How Has This Been Tested?

Manually reviewed the rendered README on a markdown previewer and tested the cloned project setup using the documented instructions. Verified the formatting, clarity, and correctness of all updated sections.

Additional Context (Please include any Screenshots/gifs if relevant)

No UI changes introduced. Below is a preview of the new social links section in the README:

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• New and existing unit tests pass locally with my changes (N/A for docs)
• I have checked my code and corrected any misspellings
• I have tagged the reviewers in a comment below in case my pull request is ready for a review
• I have signed the commit message to agree to the Developer Certificate of Origin (DCO) by adding --signoff to my git commit command

[github-actions]

Thank you and congratulations 🎉 for opening your very first pull request in student-program