Under the hood
Runner sessions now retire with a distinct max-age reason instead of generic shutdown.
Cloud/runner sessions can now retire with a dedicated "max-age" reason (max session age reached), distinct from the existing "shutdown" and "retire" outcomes, with its own "max-session-age grace" period label. The runner's Prometheus metrics now treat a max-session-age release as a clean completion, while hitting the max-lifetime hard cap still counts as an interruption.