More work on tentacles.

internal/tentacle/manager.go

@@ -65,6 +65,7 @@ type Manager struct {
 	cleanupError      error
 	remoteMutex       sync.Mutex
 	remoteOwner       *Session
+	remotePolicy      *RemotePolicy // immutable after the first child is started
 }
 
 // NewSupervisedManager launches a private lifetime helper for each Tentacle.