v0.21.2

修复：macOS 把 dsh-model 的后台服务关掉后，「修复」和 setup 会自动重新允许并启动，并确认服务真的跑起来了；以前会把加载失败当成成功，页面一直显示「服务没在运行」。

Fix: when macOS has turned off dsh-model's background services, Repair and setup now allow them again and start them, and check that they really loaded. Before, a failed load counted as success and the page kept saying the service was not running.