Viktor hit the t3 'Client and server versions differ' warning. Root cause: the daily gated autoupdate defers a user's t3-serve restart whenever that user has an active agent at the 04:00 window, so anyone busy every night (long-lived/AFK sessions) never migrates and the client/server version skew persists for days.
This design adds a small idle-gated overnight job that drains those deferrals -- restarting a deferred instance onto the current binary only when no turn is in flight (state.sqlite active_turn_id) and it's been quiet for a buffer, so the migration lands in a real quiet gap instead of killing in-flight agent turns. Reuses the autoupdate's proven backup->restart->verify->recover path via a shared helper (approach C from the brainstorm). Design doc only; no behavior change yet.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
