chore: add MIT license

[cgoldber82]

Adds the MIT license file referenced in the README.

🐕 Dogfood test — this PR should be gated by deploy-gate. The gate should:

1. Create a PP deploy request
2. Block merge until approved
3. Post a PR comment with the review link

Approve via the PP dashboard to complete the loop.

[github-actions]

✅ Permission Protocol: Approved
View receipt →

[rodchalski]

✅ Authorized by Permission Protocol

Summary: This change adds an MIT license file to the repository, which formally defines the legal terms for open-source usage and carries no technical risk. It is safe to go live, as it has no impact on app...

Environment	production
Risk	🟢 Low
Receipt	View authority proof →

_{🔒 Cryptographically signed · Verified by Permission Protocol}