去除顶部标题栏，添加菜单场景退出游戏功能

src/scenes/main_menu_scene.py

@@ -18,7 +18,7 @@ class MainMenuScene(BaseScene):
         self.font = pygame.font.Font(font_file,16)
 
         # 文本
-        self.game_info_text = self.font.render('按任意键开始游戏', True, Color.white)
+        self.game_info_text = self.font.render('按任意键开始游戏，鼠标点击退出', True, Color.white)
 
     def update(self):
         # 按键按下则切换场景
@@ -40,8 +40,8 @@ class MainMenuScene(BaseScene):
     def handle_event(self, event):
         if event.type == pygame.KEYDOWN:
             self.button_status = True
-        if event.type == pygame.MOUSEBUTTONDOWN:
-            self.button_status = True
+        elif event.type == pygame.MOUSEBUTTONDOWN:
+            return "exit"  # 主循环接收返回，为exit时设置running为False，退出游戏
 
     def __show(self, info, dest=(0, 0)):
         if not self.debug_status: