ci: add stale issue/PR management GitHub Action workflow

[snowrugar-beep]

Problem Statement

No stale issue management workflow exists. Issues and PRs accumulate without review, creating noise and making it hard to track actionable items.

Evidence

• No stale workflow in .github/workflows/

Impact

Issue tracker accumulates stale items. Maintainer overhead increases.

Proposed Solution

Create .github/workflows/stale.yml with actions/stale: mark issues/PRs as stale after 60 days of inactivity, close after 14 more days.

Technical Requirements

• Must exempt issues labeled 'pinned', 'security', or 'epic'
• Must label stale items with 'stale'
• Must comment before closing

Acceptance Criteria

1. Workflow runs on schedule (daily)
2. Issues/PRs without activity for 60 days are marked stale
3. Stale items without activity for 14 more days are closed
4. Exempt labels prevent auto-stale marking

File Inventory

• .github/workflows/stale.yml (new)

Dependencies

None.

Testing Strategy

• Dry-run workflow on test repository

Security Considerations

Security issues must be exempt from auto-closing.

Definition of Done

• Stale workflow created
• Exempt labels configured

[olaleyeolajide81-sketch]

Hi maintainer, I would love to work on this issue. I have studied the details of the issue description and I understood the requirements. I shall deliver with qualitative feedback and promptly.

[BigJohn-dev]

Allow me fix this asap

[grantfox-oss]

🦊 GrantFox — @BigJohn-dev has been assigned to this issue as part of the Official Campaign campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #35)
2. Your PR will be reviewed by the VertexChainLabs maintainers

Good luck! Track your progress on GrantFox.

[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox as part of the Official Campaign campaign!

@BigJohn-dev's PR #83 was approved and merged by @snowrugar-beep.

🏆 @BigJohn-dev: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (681 total points). Track your full progress on GrantFox.

👏 Great work, @BigJohn-dev! Keep contributing to VertexChainLabs.