Add issue closure recommendation workflow

[denelon]

Summary

• Add an experimental weekly and manually targeted agentic workflow that identifies open issues with recent merged same-repository pull request references.
• Require semantic scope equivalence and post-merge corroboration before recommending maintainer review.
• Add a custom safe-output handler that binds recommendations to trusted collected evidence, revalidates issue and pull request state, and only adds Needs-Attention plus a templated comment.
• Stage all writes outside microsoft/winget-cli, preserve idempotency, and never close issues or remove labels.
• Use repository-compatible recent-window terminology so the workflow passes spelling validation.

Created with GitHub Copilot assistance.

Validation

• Compiled the Markdown source with gh aw compile issue-closure-recommendation --actionlint.
• Scheduled staged trial rejected all four recent false-positive candidates: https://github.com/denelon/gh-aw-trial/actions/runs/30768085305
• Targeted staged trial validated a high-confidence recommendation for issue 2129: https://github.com/denelon/gh-aw-trial/actions/runs/30768328394

References

Resolves #6422