fix(ci): add state=closed param to issues API call

[CalvinAllen]

Summary

The GitHub Issues API defaults to returning only open issues. The workflow wasn't finding any closed issues to check for PR references.

Added ?state=closed to the API call to fetch closed issues.

Root Cause

# Without state param - returns nothing (only open issues)
gh api repos/CodingWithCalvin/VSToolbox/issues -q '.[] | select(.state == "closed")'

# With state=closed - returns closed issues
gh api "repos/CodingWithCalvin/VSToolbox/issues?state=closed" -q '.[]'