The AMQP transport is gone from the control plane and the hosts (mesh-controller #112,
mesh-host #39). On the way: no build had ever recorded its bases, so every bases-first order
walked an empty graph; the builder now reports what it was handed and the graph is read from
builds (mesh-controller #113/#114). Issue 131 is resolved by the forge module's merge event,
the control plane following it, and those edges.