feat: 优化UI操作逻辑，增加退出游戏按钮

scenes/main_menu.tscn

@@ -44,6 +44,15 @@ theme_override_fonts/font = ExtResource("1_l6cm7")
 theme_override_font_sizes/font_size = 36
 text = "加入局域网游戏"
 
+[node name="QuitGame" type="Button" parent="." unique_id=70898198]
+offset_left = 932.0
+offset_top = 959.0
+offset_right = 1248.0386
+offset_bottom = 1058.0
+theme_override_fonts/font = ExtResource("1_l6cm7")
+theme_override_font_sizes/font_size = 36
+text = "退出游戏"
+
 [node name="CreateGameUI" type="Node2D" parent="." unique_id=462604530]
 visible = false
 position = Vector2(585, 355)
@@ -150,6 +159,7 @@ text = "设置"
 
 [connection signal="pressed" from="StartGame" to="." method="_on_start_game_pressed"]
 [connection signal="pressed" from="JoinGame" to="." method="_on_join_game_pressed"]
+[connection signal="pressed" from="QuitGame" to="." method="_on_quit_game_pressed"]
 [connection signal="pressed" from="CreateGameUI/CreateGameButton" to="CreateGameUI" method="_on_create_game_button_pressed"]
 [connection signal="pressed" from="CreateGameUI/Warn/WarnButton" to="CreateGameUI" method="_on_warn_button_pressed"]
 [connection signal="pressed" from="JoinGameUI/JoinGameButton" to="JoinGameUI" method="_on_join_game_button_pressed"]

scenes/settings.tscn

@@ -96,10 +96,10 @@ offset_bottom = 60.0
 theme_override_font_sizes/font_size = 25
 
 [node name="SaveButton" type="Button" parent="." unique_id=1377249836]
-offset_left = 150.0
-offset_top = 1321.0
-offset_right = 314.0
-offset_bottom = 1398.0
+offset_left = 147.0
+offset_top = 1315.0
+offset_right = 311.0
+offset_bottom = 1392.0
 theme_override_fonts/font = ExtResource("2_6wm04")
 theme_override_font_sizes/font_size = 30
 text = "保存设置"
@@ -120,7 +120,7 @@ offset_right = 550.0
 offset_bottom = 1394.0
 theme_override_fonts/font = ExtResource("2_6wm04")
 theme_override_font_sizes/font_size = 30
-text = "取消"
+text = "返回"
 
 [node name="LoadButton" type="Button" parent="." unique_id=2015694853]
 offset_left = 135.0