Adopt shared stale-issue triage in agent-plugins #614

🤖 Generated by the Agentic Engineer

Outcome

Adopt the portfolio inactivity policy through the maintained shared workflow: a reminder and stale label after 90 inactive days, then closure as not planned after 30 more inactive days. New activity must remove stale and recover the issue.

Acceptance

• Pin a thin daily caller to the reviewed published shared source.
• Exercise a read-only preview in the caller pull request; manual execution defaults to preview.
• Preserve protected issue types and labels, automation-owned issues, pull requests and branches.
• Verify managed label definitions before activation and observe the first native live run after protected merge.
• Record delivery and execution evidence before closing this task.

Part of devantler-tech/.github#806. Shared-source publication and label convergence are tracked in devantler-tech/.github#807. Priority Medium, Effort Low, service class Standard.