T1: the seat settle applies a delayed nak with the bus's own delay (ADR 0664 §1, issue 1748)

Claude-Session: https://claude.ai/code/session_01JG73KEq4zoDfM9WtYpcQgZ

node-tools/internal/bus/seat_pull_test.go

@@ -58,6 +58,21 @@ func TestAHolderPullsOneMessageWhenItHasRoom(t *testing.T) {
 	if err != nil || again == nil || string(again.Body) != `{"id":"a2"}` || again.Delivered != 2 {
 		t.Fatalf("the message handed back = %+v, %v", again, err)
 	}
+	// Issue 1748: a message settled with a delay is not given again at once, is after it, one delivery higher; a delay
+	// of 0 settles nothing.
+	if err := conn.SeatSettleAfter("messenger", again.ID, 0); err == nil {
+		t.Error("a delay of 0 was accepted")
+	}
+	if err := conn.SeatSettleAfter("messenger", again.ID, 300*time.Millisecond); err != nil {
+		t.Fatal(err)
+	}
+	if early, err := conn.SeatPull("messenger", "SEAT_OPERATOR_CHANNEL_worker", 0); err != nil || early != nil {
+		t.Fatalf("a message given again after a delay came at once: %+v, %v", early, err)
+	}
+	late, err := conn.SeatPull("messenger", "SEAT_OPERATOR_CHANNEL_worker", 2*time.Second)
+	if err != nil || late == nil || late.Delivered != 3 {
+		t.Fatalf("the message given again after its delay = %+v, %v", late, err)
+	}
 	if _, err := conn.SeatPull("telegram", "SEAT_OPERATOR_CHANNEL_worker", 0); err == nil || !strings.Contains(err.Error(), "membership lists") {
 		t.Errorf("a channel pulled the router's work: %v", err)
 	}