dsh-indexbookmark: A Conversation Question Index Plugin for the DSH Web Interface

`dsh-indexbookmark` is an open-source plugin designed to address the challenge of quickly locating previous questions in long conversations within the DSH Web interface. It adds an index button to the right side of the input box. Core features include: listing all messages with global sequence numbers; clicking a list item automatically scrolls to it and flash-highlights it for 1.6 seconds; supporting search filtering, custom pagination, and lazy loading; providing a session-level in-memory caching mechanism; and supporting automatic light/dark mode switching as well as Chinese/English language switching. To install, make sure `dsh` and `pnpm` are installed in the environment, then run `dsh plugin --profile web add github:cuhaitiang0405-collab/dsh-indexbookmark` in the command line. After installation, restart the web version of DSH for the plugin to take effect. When using it,