[PeerX Backlog # 51] Add a `LICENSE` file (MIT) and update README's license badge

[ameeribro4-sudo]

Problem Statement
README.md advertises MIT and shows a badge, but LICENSE is not
committed. The line near the end of README says "No LICENSE file is
currently committed — add one before publishing. Until then, all rights
reserved by default."

Why it matters
For an open-source project, missing license is a blocker. The badge is
truthful only relative to the publishing break.

Acceptance Criteria

• LICENSE committed (full MIT text, copyright "PeerX Contributors").
• Cargo.toml [package].license = "MIT".
• README is updated to remove the disclaimer.

Files Affected

• LICENSE (new), Cargo.toml, README.md.

Difficulty / Effort 🥉 / XS
Labels documentation, legal, priority/critical

[GBOYEE]

Hi team — I'd like to take this on as part of the GrantFox campaign. I'll write the documentation and open a PR referencing this issue shortly.

[sanusishafii989]

I can resolve this licensing mismatch right away.

I will add the standard MIT LICENSE file with the required "PeerX Contributors" copyright text, update the license field in Cargo.toml to "MIT", and remove the temporary disclaimer block at the bottom of the README.md so the codebase properly reflects its open-source status.

Ready to submit a quick, clean PR for this. Please assign it to me!

[grantfox-oss]

🦊 GrantFox — @sanusishafii989 has been assigned to this issue as part of the Official Campaign | FWC26 campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #51)
2. Your PR will be reviewed by the OpenPeerX maintainers

Good luck! Track your progress on GrantFox.