Give each workflow run a parent task with no agent

internal/agents/audit.go

@@ -94,6 +94,9 @@ func (m *Manager) startAudit(ctx context.Context, projectID string) error {
 		return nil
 	}
 	for _, t := range tasks {
+		if t.WorkflowStage == nil {
+			continue
+		}
 		m.auditError(ctx, t, fmt.Sprintf("The audit of %s didn't start: %v. Discard this task to let audits continue; the next commit on %s starts one.", short(head), err, project.DefaultBranch))
 	}
 	return err
@@ -126,7 +129,7 @@ func (m *Manager) dismissAudit(taskID string) {
 		slog.Error("dismiss audit", "task", taskID, "err", err)
 		return
 	}
-	if !task.Background || task.Status != api.TaskStatusActive {
+	if !task.Background || task.Status != api.TaskStatusActive || task.WorkflowStage == nil {
 		return
 	}
 	output, _, err := m.store.StageResult(ctx, taskID)