muxr v3.5.1 Fix: recycle hung ~600s then SIGKILL for interactive sessions (#8). - fix(recycle): gate on the readiness idle signal and let muxr send the exit keystroke itself, rather than waiting on an agent self-/exit that an interactive CLI can never perform. Mirrors `upgrade`. Verified end-to-end against a fake never-self-exiting agent (completes in ~6s vs a 600s hang).