Verify prepared notification ownership and cleanup

internal/usecase/prepared_notification_test.go

@@ -18,3 +18,25 @@ func TestPreparedNotificationChecksContextBeforeInvocation(t *testing.T) {
 		t.Fatalf("called=%v error=%v", called, err)
 	}
 }
+
+func TestPreparedNotificationPanicClearsClaimedPayload(t *testing.T) {
+	runner := NewRunner(&fakePromptRepo{def: promptDef(domain.FormatText, domain.ValidationNone, 0)},
+		&fakeExecutionProfileRepo{profiles: map[string]*domain.ExecutionProfile{"exec": defaultExecutionProfile()}},
+		defaultArtifactReader(), defaultRenderer(), &fakeLLM{resp: &domain.GenerateResponse{Content: "ok"}}, nil, nil)
+	handle, err := runner.PrepareExecution(context.Background(), domain.RunRequest{PromptID: "p", ProfileID: "exec", Inputs: singleInputRef(), OnPrepared: func(context.Context, *domain.PreparedRun) { panic("notification") }})
+	if err != nil {
+		t.Fatal(err)
+	}
+	payload := handle.payload
+	func() {
+		defer func() {
+			if recover() == nil {
+				t.Error("expected panic")
+			}
+		}()
+		_, _ = runner.RunPrepared(context.Background(), handle)
+	}()
+	if payload.prepared != nil || payload.onPrepared != nil || payload.directKey != "" || handle.payload != nil {
+		t.Fatal("claimed payload retained private state")
+	}
+}