lijian-ui/dsh-term: DSH Sidebar-style Local Terminal

`dsh-term` is a local terminal plugin designed specifically for the DSH Web GUI to address interactive debugging needs. It uses `node-pty` to provide real pseudo-terminal sessions, implements a multi-tab UI based on `xterm.js`, and adopts a hot-swappable architecture that can be integrated without modifying the source code. The plugin supports layout integration and automatic CWD configuration, and is provided in a collapsed state by default. The current Version A only supports local user terminals, with SSH functionality to be added in the future.