chore: bootstrap production CODEOWNERS enforcement

[munisp]

Purpose

Adds the first .github/CODEOWNERS file to the production base branch. This bootstrap must merge before an administrator enables required code-owner review, because GitHub evaluates CODEOWNERS from the pull request base branch.

Scope

• Exactly one tracked file: .github/CODEOWNERS
• Routes dependency-exception, release/container, authorization and policy controls to @munisp pending authorized managed-team ownership
• No workflow, production configuration, dependency, environment, secret, image, or deployment changes

Required review and follow-up

• Obtain an independent review under the current protected-branch rule.
• After this PR is merged, validate CODEOWNERS on production, then an authorized administrator may enable the approved two-review plus CODEOWNER requirement.
• Do not force merge or bypass protections.

Validation

• git diff --cached --check passed before commit.
• Bootstrap commit: 20184f94453c4c3f7e478eb2ddeeef4659b3a6fe.