dsh-plugin-restart-desktop: Add a sequential restart button to the DSH Desktop sidebar

`dsh-plugin-restart-desktop` is a single-purpose DSH Desktop plugin designed to inject a "Restart Desktop" button at the bottom of the sidebar. After clicking the button and confirming twice, it triggers an ordered restart of the desktop main process by calling `desktopActions.requestRestart()`, displaying a loading layer during the process. This plugin supports the DSH language system, allowing for real-time switching between Chinese and English text in settings, but it is applicable only to the desktop profile; calling it under the headless web profile will return a failure prompt. During installation, the `package.json` of the desktop profile needs to be modified to add the plugin path to `dependencies` and...