Auto-remove status labels on issue close

[vmvarela]

Description

When issues are closed, the status:* labels (status:ready, status:in-progress, status:review) remain attached. This creates noise and makes label-based filtering unreliable.

Create a GitHub Actions workflow that automatically removes all status:* labels when an issue is closed.

Acceptance Criteria

• GitHub Action triggers on issues event with closed type
• Removes status:ready, status:in-progress, status:blocked, and status:review labels from the closed issue
• Does not fail if the issue has no status:* labels
• Works for both manual close and close-via-PR

Notes

• Can use actions/github-script to call the GitHub API directly
• This was identified as an improvement in the Sprint 2 Retrospective