The spec is the working system: HAL's 99-hal.conf, restated as
10-mesh.conf so lexical include order makes the mesh's answer the one
that wins while the predecessor's file is still on disk. Subsystem
stays the stock config's — first-set wins and it sits before the
Include. Port 22 from anywhere, said in listens with its reason: the
machines that need the door are exactly the ones not on the mesh yet,
and locking the operator out is the one failure a firewall must never
arrange.
