Pull the Node build seat's asks beside the tools, delivery first and at most the node's capacity (issue 1887 A3node, ADR 0525 §2-§6)

modules/mesh-build-node/cmd/mesh-build-node/module.go

@@ -63,6 +63,11 @@ type Module struct {
 	// sets floorOf(node), and a zero Floor checks nothing.
 	Floor buildstep.Floor
 
+	// Settings is the module's settings file, which holds the node's build capacity (buildstep.CapacitySetting); Capacity,
+	// when set, answers it instead (a test).
+	Settings string
+	Capacity func() int
+
 	spacesOnce sync.Once
 	workspaces *buildstep.Workspaces
 	mu         sync.Mutex // guards Recipe