Let a walk wait for its delivery's word, and serve the delivery's owner (hq ADR 0239)

While the mesh-delivery seat has a holder on record, a merge that moves no
core module opens its walk and asks nothing until mesh-delivery or a person
says go; nothing of it is registered before its turn, so no other send
carries it. The controller keeps the planner, the gate, sending and the
walk, and gains the verbs the owner asks with: delivery-plan, -order,
-check (a group composed as one future state), deliver, delivery-stop,
delivery-walks; every walk kept is said as plan-moved.

cmd/mesh-controller/upgrades.go

@@ -422,6 +422,9 @@ func (f following) SourceMoved(ctx context.Context, m link.SourceMoved) error {
 				strings.Join(also, ", "), plan.Repository)
 		}
 	}
+	// **Whether it waits for its delivery's word** (novox/hq ADR 0239): while the mesh-delivery seat has a
+	// holder on record, a walk that moves no module on the controller's own path is opened and waits.
+	plan.Delivery = awaitsFor(entries, movedNames)
 	if hasCycle(plan.Tiers, edges) {
 		fmt.Printf("  the last tier depends on itself: %s — built together, in no order\n",
 			strings.Join(plan.Tiers[len(plan.Tiers)-1], ", "))
@@ -451,6 +454,14 @@ func (f following) SourceMoved(ctx context.Context, m link.SourceMoved) error {
 		fmt.Printf("  %s package source from it, so they are rebuilt and their own source record "+
 			"is left where it is\n", strings.Join(also, ", "))
 	}
+	if plan.Waiting() {
+		plan.Note = waitingNote(plan)
+		if err := inv.SavePlan(ctx, &plan); err != nil {
+			return notNow(err)
+		}
+		fmt.Printf("  %s waits for %s's word before its first tier is asked\n", plan.ID, plan.Delivery.Awaits)
+		return nil
+	}
 	if err := askTier(ctx, inv, &plan); err != nil {
 		return notNow(err)
 	}