Add Happy Number

[dhanushrajvr]

Name: V R Dhanush Raj
Description: I have added a program that determines whether a given number is a happy number

Body:

• My code follows the project's style guidelines
• I have tested my code thoroughly
• My project runs without errors
• No external dependencies added (unless necessary)
• I am participating in GSSoC 2026

Advantage:

• You would learn loops, set datatype
• You would learn list comprehension

Closes #174
It is a PR linked to the previous PR #108

[vercel]

@dhanushrajvr is attempting to deploy a commit to the Anuj's projects Team on Vercel.

A member of the Team first needs to authorize it.

[github-actions]

🎉 Thank you for your contribution!

Your Pull Request has been merged successfully.

We appreciate the time and effort you put into improving this project. Contributions like yours help the repository grow and stay useful for everyone.

If you'd like to contribute again, please check the open issues and make sure you are assigned before opening another Pull Request.

Thanks again for your support! 🙌

[github-actions]

Thanks @dhanushrajvr! I've added you to the contributors list.