add animation playback

src/app.cpp

@@ -987,7 +987,7 @@ void App::ui_thread_main()
         // move the task list locally to free the queue for other threads
         {
             std::unique_lock<std::mutex> lock(ui_task_mutex);
-            ui_cv.wait_for(lock, std::chrono::milliseconds(100), 
+            ui_cv.wait_for(lock, std::chrono::milliseconds(idle_ms), 
                 [this] { return ui_tasklist.empty() && ui_running ? false : true; });
             working_list = std::move(ui_tasklist);
         }