OpenShell supervisor
The supervisor consumes the shared isolation backend contract. Its gateway session, canonical process attachment, and TCP readiness do not require SSH or a Unix host.
TCP readiness opens only after the gateway accepts the authenticated session. Session loss closes readiness; accepted reconnection restores it. Dropping the readiness guard closes the listener. A requested Unix readiness endpoint fails explicitly on unsupported hosts, even before session acceptance.
The optional Unix SSH adapter remains separate from boundary-based process I/O.
Local Unix process signaling retains its existing signal surface, including
SIGQUIT. Remote signals use the backend-neutral BoundarySignal contract.
These portable control-plane foundations do not qualify a platform isolation backend or enable a Windows workload runtime.