feat: support max running tasks config (#112)

ui/flutter/lib/app/modules/task/controllers/task_downloading_controller.dart

@@ -3,5 +3,11 @@ import 'task_list_controller.dart';
 
 class TaskDownloadingController extends TaskListController {
   TaskDownloadingController()
-      : super([Status.ready, Status.running, Status.pause, Status.error]);
+      : super([
+          Status.ready,
+          Status.running,
+          Status.pause,
+          Status.wait,
+          Status.error
+        ]);
 }