NTM — optional pane adapter

NTM hosts explicit agent roles in persistent panes. It is transport, not an AgentOps lifecycle controller. The caller chooses the panes, roles, commands, write scopes, and stopping point.

Robot surfaces work because they report what the pane is doing, not what was sent to it; a dispatch layer that only proved delivery would let every dead worker look busy.

Judge pane liveness by the truth-stack, strongest first: new artifacts on disk, then transcript growth, then robot state and attention flags, then bare process existence. A successful prompt send sits below all of these and proves nothing about work.

Named failure mode — kill-the-witness: restarting a stuck pane before capturing its state, destroying the only evidence of why it stalled.