Judge the grants step on the declaration it sends, so nothing composed between the check and the send slips through (review of #230)

The guard composed its own declaration ahead of the send; now sendToEach
judges the one it composed and stamped, and refuses it unsent.

cmd/mesh-controller/push.go

@@ -1236,6 +1236,17 @@ func sendToEach(ctx context.Context, open *stores, names []string) ([]string, er
 			continue
 		}
 		numbered.stamp(&declared)
+		// **The grants step sends the user list and nothing else** (novox/hq issue 490): judged on this very
+		// declaration, the one sent, so nothing composed between a check and the send can slip through.
+		if everyBuildKept(ctx) {
+			other, err := grantsOnlyIn(ctx, open, name, plan, declared)
+			if err != nil {
+				return nil, err
+			}
+			if other != "" {
+				return nil, fmt.Errorf("%w: %s", errNotGrantsOnly, other)
+			}
+		}
 		reportLeftOut(name, declared)
 		sending = append(sending, readyNode{name, declared})
 	}