DSH Unread Dot: Display DSH Unread Badge and Bubble Notification Sound on macOS Dock

`dsh-unread-dot` is a DeepSeek Harness (DSH) plugin designed specifically for macOS Chrome, aimed at addressing the issue of background session status reminders being too subtle. Built on the Chrome Badging API, this plugin requires no system notifications or additional permissions and takes effect after DSH Web is installed as a PWA. Its core features include: a red dot on the Dock icon to indicate a session is running, a numeric badge to show unread results or pending items, and an embedded bubble notification sound when events occur; the badge clears automatically once the user returns to the app. The plugin uses a cross-window lock to ensure the notification sound plays only once across multiple windows, and it alerts only for events that occur while the user is away. To use it, you must first install DSH Web as a PWA in Chrome.