Add validator script for protocol metadata JSON files

[Kanz001]

This PR introduces a Python script (scripts/validate_protocol.py) that validates JSON metadata in the testnet/ folder.
It ensures required fields (name, description, links, categories) are present, helping maintain consistency.

[Kanz001]

Hi team 👋,

This PR introduces a small utility script (scripts/validate_protocol.py) that validates JSON files in the testnet/ folder.
It checks that each file includes the required fields: name, description, links, and categories.

The goal is to help maintain consistency across protocol metadata and reduce human error during contributions.
It’s a small addition but should be useful for keeping files structured correctly.

Thanks for reviewing! 🚀