dsh-turnbar: DeepSeek Harness Chat Progress Bar

dsh-turnbar is a video-style timeline plugin designed for the DeepSeek Harness chat interface, aiming to make it easier to navigate back through long conversations. It provides a full-map progress bar, hover previews, in-session search (supports ⌘K), context fuel gauge alerts, chapter tick marks, and quick navigation via ⌘↑/⌘↓. It supports clicking or dragging to jump to a position and degrades gracefully. The installation command is `dsh plugin --profile web add dsh-turnbar`, and it requires DeepSeek Harness >= 0.1.0-rc.5.