Under the hood
New telemetry tracks when the artifact tool disappears and reappears mid-session.
Two telemetry events, tengu_artifact_tool_recovered and tengu_artifact_tool_withheld, now track when the artifact tool disappears from a session and reappears. Withholding reasons include surface_excluded, nested_child_session, admin_policy/subscription_ineligible, and switched_off; this is telemetry only, with no user-facing behavior change.