feat(ci): codeowners enforcement workflow

[erikburt]

Adds a CODEOWNERS enforcement workflow.

This workflow:

1. Checks out repo (at PR branch)
2. Checks if there's a CODEOWNERS file at .github/CODEOWNERS or in the root of the repository
3. Attempts to find a PR comment (html comment fingerprint)
4. If no CODEOWNERS file is found - upsert the comment
5. If CODEOWNERS file is found:
   • If no previous comment - do nothing
   • If previous comment - edit to a thank you
6. If no CODEOWNERS found - fail the action

Testing

• https://github.com/smartcontractkit/releng-test/pull/133

This PR:

• Initial commit (fail): https://github.com/smartcontractkit/gha-org-workflows/actions/runs/17246297685/job/48936695738?pr=13
  • See below comment history
• Un-reversed booleans (success): https://github.com/smartcontractkit/gha-org-workflows/actions/runs/17246339976/job/48936851174?pr=13
  • feat(ci): codeowners enforcement workflow #13 (comment)

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DX-1647

[github-actions]

Thank you for adding a CODEOWNERS file - @erikburt.