Refuse a declaration composed from an older assignment generation than the machine applied (hq issue 234)

A newer sequence carrying an older view of the assignments undeclared four
assigned modules on 2026-10-04; the sequence cannot tell it, the generation
can. The engine keeps the highest generation it applied, refuses an older one
before reading the machine unless the declaration is a gate's put-back, and
says the refusal in its report so the controller can name the sender. A
declaration without a generation is applied as before, and every report says
it reads one, so the controller sends it only to engines that do.

internal/declaration/order_test.go

@@ -35,3 +35,25 @@ func TestAnOrderBelowZeroIsRefused(t *testing.T) {
 		}
 	}
 }
+
+// **The assignment generation it was composed from, and whether it is a put-back** (novox/hq issue 234):
+// absent is no claim; below zero is none the mesh assigns; a carried bundle puts nothing back.
+func TestADeclarationCarriesItsGenerationAndWhetherItIsAPutBack(t *testing.T) {
+	d, err := Parse([]byte(withOrder(`"sequence":3,"generation":41,"put_back":true,`)))
+	if err != nil {
+		t.Fatalf("a declaration carrying its generation was refused: %v", err)
+	}
+	if d.Generation != 41 || !d.PutBack {
+		t.Fatalf("read generation %d, put-back %v", d.Generation, d.PutBack)
+	}
+	if d, err = Parse([]byte(withOrder(``))); err != nil || d.Generation != 0 || d.PutBack {
+		t.Fatalf("a declaration with no generation read as %+v, %v", d, err)
+	}
+	if refusal := refusalFor(t, withOrder(`"generation":-2,`)); !strings.Contains(refusal.Error(), "below zero") {
+		t.Errorf("a generation below zero was refused for something else: %v", refusal)
+	}
+	if _, err := ParseTrusted([]byte(withOrder(`"generation":3,"put_back":true,`))); err == nil ||
+		!strings.Contains(err.Error(), "put-back") {
+		t.Errorf("a carried bundle said it was a put-back and was not refused for it: %v", err)
+	}
+}