dsh-anchor-rail: DSH Web Session Anchor Rail

`dsh-anchor-rail` is a DeepSeek Harness plugin designed to address the difficulty of manually scrolling to locate content in long conversations. It displays anchors for all user questions in a fixed left rail, supporting hover-to-expand details and click-to-navigate. Core features include displaying all questions, grouping compressed segments with dashed separators, providing a compact scrolling fallback, highlighting the current item, and retaining historical data. The plugin uses the Host to read raw logs and the Client to render interactions, automatically handling data loading and navigation, thereby improving the efficiency of developing and reviewing long conversations.