DeepSeek Harness Plugin: dsh-changes-panel

`dsh-changes-panel` is a file change tracking plugin for DeepSeek Harness, designed to address the difficulty of tracking code modifications in long conversations. It provides a real-time diff panel in the web interface, supports drag-to-resize width, and includes logic to automatically expand or collapse based on the working set state. The panel displays added (A) and modified (M) file statuses, supports expanding to view detailed code changes, and offers a full-screen mode. The bottom action bar allows users to accept or revert files and automatically updates the baseline. The plugin supports dark themes and provides session-level isolation management. Installation requires building dependencies and configuring a local path in `package.json`. It currently does not support tracking deletion statuses or persistent storage.