Add "Back to Top" button

[abdullahlko]

Description:
Implement a "Back to Top" button fixed at the bottom-right corner of the page. Clicking it should smoothly scroll the user to the top.

[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. 😊

[abdullahlko]

Please assign this issue to me and add GSSOC'25 and appropriate level labels.

[iffasadiq]

please assign it me as GSsoc

[Akashshelke07]

Hi @iffasadiq, since @abdullahlko raised the PR first, I am going to assign it to him. You can contribute to another issue