Let a node composing itself hand a module exactly when the vault judged its plan handed, through one rule (catalogue.AssignmentHands), so the vault and the node never judge postgres's secrets two ways again (issue 774)

go/compose/input.go

@@ -142,6 +142,10 @@ type Node struct {
 	Place Place
 	// Assigned is the modules assigned to it, in the order the controller reads them (inv.Assigned).
 	Assigned []string
+	// Handed is, by module, whether the vault judged it handed to the provisioner when it answered this node's own
+	// secrets (catalogue.AssignmentHands of the plan in its assignment): the node's own composition hands exactly those
+	// (catalogue.Rendering.Assigned, issue 774). Nil where the vault said nothing of it, as for the controller.
+	Handed map[string]bool
 	// Capabilities are the ones present on it (inv.ProfileOf).
 	Capabilities map[string]bool
 	// PublicDomain is the domain it composes its routed names under (inv.PublicDomainOf).