Summary

• add a reusable stale policy workflow template for issues and pull requests
• mark inactive issues after 60 days and PRs after 30 days, then close after a 14-day grace period
• exempt pinned, blocked, security, tracking, and work-in-progress items where applicable

Validation

• ruby -e "require 'yaml'; YAML.load_file('workflow-templates/stale.yml'); puts 'YAML syntax OK'"