dsh-jumpbar: DSH Web Message Navigation Bar

The `dsh-jumpbar` plugin, maintained by delaydai, provides long-conversation navigation for DeepSeek Harness (DSH) Web. It generates a map-like navigation bar on the right side of the interface, supporting Minimap-style positioning, hover previews, click-to-jump, and drag-based fast-forward. With real-time updates and zero overhead, it helps users quickly locate context in long conversations without modifying host code.