Docs : Add Table of Contents in README

[imBharathkumarp]

• Add Table of Contents with Toggle Button (Space Saving)
• For quick and Improved Navigation
• I'm participant of OSCI'25, @Sushma-1706 please assign me.

[github-actions]

Thank you for raising this issue!

We'll review it as soon as possible. We truly appreciate your contributions! ✨

Meanwhile make sure you've visited the README.md, CONTRIBUTING.md, and CODE_OF_CONDUCT.md before creating a PR for this. Also, please do NOT create a PR until this issue has been assigned to you. 😊