Revert "feat: implement temporary code freeze with core-platform as sole CODEOWNERS"

[cryptodev-2s]

Reverts #6947

---

Note

Restores detailed CODEOWNERS mappings and re-enables codeowner validation in Yarn constraints.

• Repo governance:
  • Restore detailed CODEOWNERS rules per team and package; add ownership for .github/ to @MetaMask/core-platform.
• Tooling (Yarn constraints):
  • Re-enable expectCodeowner check for child workspaces.
  • Reintroduce cachedCodeownersFile and full expectCodeowner implementation to validate package-level rules and core-platform co-ownership of CHANGELOG.md and package.json.

^{Written by Cursor Bugbot for commit 8dd34e9. This will update automatically on new commits. Configure here.}

[Gudahtt]

LGTM!