Add explicit MIT license

[jmcte]

Summary

• Add an explicit MIT LICENSE file.
• Leave repository code unchanged.

Governing Issue

No governing issue is linked; this is an organization metadata hygiene update across public repositories.

Validation

• License file was added through GitHub contents API on a dedicated branch.
• Verified the PR branch contains LICENSE.

Bootstrap Governance

This change only adds repository licensing metadata and does not alter bootstrap behavior, generated policy, secrets, workflows, or runtime configuration.

Merge Automation

Auto-merge is blocked until required checks and review policy are satisfied.

Notes

Direct default-branch updates are blocked by branch protection, so this change is submitted as a narrow PR.

[pheidon]

Pheidon second-pass review: approved. The diff is limited to adding a standard MIT LICENSE file. I checked the current PR checks; the latest CI Gate, PR description validation, secret scan, and attestation jobs are passing. The earlier failing checks shown in the rollup are stale from a prior run, not current blockers.