dsh-meow-cat: Add a round-end toast for DSH Web

`dsh-meow-cat` is a lightweight plugin designed for the DSH Web platform, aiming to provide visual and auditory feedback at the end of a conversation turn. Its core function is to trigger a pure CSS animation of a cat running across the bottom and play a "Meow~" sound effect (WAV format, no external audio file dependencies) synthesized at runtime in memory. The plugin consists of two JavaScript files, `lib/index.js` and `lib/client.js`, plus a single line of bundle patch, with no additional dependencies. The installation command is `npx dshpub add dsh-pub/dsh-meow-cat --profile web`, and the process must be restarted after installation. Users can view the turn count via the status interface or adjust configuration settings such as volume and polling interval using the browser console. Requires...