mesh/merge-gate pass: builds mesh-host → ace, g14, novox, shanks; no bus step; every machine composes with the change as it did without (4 of 4 compose)
Once a mesh directory's mode and owner go only through a walk that follows no
link another account could make, a directory behind such a link is refused
and its module gated: on the control-node that could stop the controller.
The operator is to be told which directories that walk would refuse on every
node before it lands. So the engine judges the declaration it keeps with the
same walk, making and changing nothing: on a signed ask from the controller
(mesh.node.<node>.ask.judge-directories, held to the hand-over's checks) and
as `nox-mesh-host judge-directories` at the machine.
