Move t3 from pinned stable (0.0.24, catalog capped at opus-4-7) to the nightly
channel so new models (Opus 4.8) land as t3 ships them. t3-autoupdate (daily
systemd timer) pulls t3@nightly, but applies the Keel-incident lesson: it
health-checks the new binary on a throwaway serve and AUTO-ROLLS-BACK on
failure, and restarts only IDLE per-user instances (defers any with an active
agent child) so an in-flight session is never killed by an update.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
