dsh-web-attention-badge: Adding Session Alerts to the DSH Web UI

`dsh-web-attention-badge` is a DSH plugin designed for the DeepSeek Harness Web UI, aimed at helping developers intuitively monitor session states. This plugin provides reminders through three approaches: a badge displayed in the upper-left corner of the interface, a count shown in the browser tab title, and a color-changing whale favicon. Specifically, the Amber color represents sessions awaiting user input, while the Green color indicates completed but unopened sessions. These reminders share built-in session storage counts, requiring no additional host code or transport layer, and the badge supports click-through, without obstructing sidebar operations. Installation is straightforward, achieved via the `dsh plugin` command for automatic registration and updates, supporting installation from local sources or GitHub. Users can customize by modifying the `lib/client.js` file through the