A node is given how it hears its declarations as it enrols

The node's declaration consumer was asserted only when the control plane
started, so the first machine of a mesh, enrolling after the control
plane was up, joined and then heard nothing: its host retried 'consumer
not found' for ever (novox/hq issue 146).

internal/link/serve.go

@@ -73,6 +73,8 @@ type Server struct {
 	inbound Inbound
 	bus     Bus
 	js      *broker.JetStream
+	// consumers makes a node's declaration consumer as it enrols; the bus connection, or a stand-in.
+	consumers interface{ EnsureConsumer(broker.Consumer) error }
 
 	enroller Enroller
 	listener Listener
@@ -383,6 +385,7 @@ func (s *Server) enrolling(ctx context.Context, m Control) {
 		default:
 			reply = accepted
 			s.log.Printf("enrolled %s", accepted.Node)
+			s.hearsItsDeclarations(accepted.Node)
 		}
 	}
 
@@ -402,6 +405,24 @@ func (s *Server) enrolling(ctx context.Context, m Control) {
 	_ = m.Took()
 }
 
+// hearsItsDeclarations makes the consumer a node reads its declarations through, as it enrols and
+// before it is answered.
+//
+// **Created at enrolment, as the consumer's own doc has always said** (novox/hq 04-ISSUES/146). It
+// was asserted only when the control plane started, so the first machine of a mesh — which enrols
+// after the control plane is already up — joined and then heard nothing, its host retrying "consumer
+// not found" for ever. Failing here is said and does not unspend the token: the next start of the
+// control plane asserts it again.
+func (s *Server) hearsItsDeclarations(node string) {
+	if s.consumers == nil {
+		return
+	}
+	if err := s.consumers.EnsureConsumer(broker.NodeConsumer(node)); err != nil {
+		s.log.Printf("%s enrolled, and how it hears its declarations could not be made — it will hear "+
+			"nothing until the control plane next starts: %v", node, err)
+	}
+}
+
 // wasBuilt keeps what a builder said, whichever way it went.
 //
 // This is for results nobody was waiting for. A build asked for with `build` is answered directly