docs: Add GSSoC branching conventions reference manual

[Pratikshya32]

We should add a standardized branching conventions GSSoC guide to CONTRIBUTING.md.

cc @Priyanshu-byte-coder

[Pratikshya32]

/assign

Hello @Priyanshu-byte-coder, please assign this issue to me. Thank you! ✨

[anshul23102]

I can add the GSSoC branching conventions reference manual. Will document branch naming and workflow standards.

/assign

[sakshiwankhade026-coder]

Hi 👋

I would like to work on this issue under GSSoC'26.

I have previously contributed to open-source projects and have 5 PRs successfully merged. I have gone through the issue requirements and would be happy to work on the implementation while following the project's guidelines and maintaining code quality.

Please assign this issue to me if it is available.

Thank you!

[github-actions]

Assigned to @sakshiwankhade026-coder! You have 7 days to open a PR. No PR after 7 days = auto-unassigned so others can pick it up. Good luck!