Persistent terminal

Persistent Terminal is the reference trusted widget. The panel is a hash-approved ABI v2 side module; the backend session is the typed dev.formless.tty Host capability.
Host owns process lifetime, terminal size, output history and reconnection. Click owns rendering, keyboard/touch input, focus, and panel layout. Closing a panel instance need not destroy the persistent session; policy controls when the Host-side resource ends.
This is deliberately not a Canvas shell with ambient Host command authority. The widget declares the TTY capability and Click brokers each operation.