dsh-tree: A Tree Display Plugin

The dsh-tree plugin for DeepSeek Harness (DSH) is maintained by developer istone and is designed to visualize agent configurations or hierarchical data as a tree structure. Built entirely with Node.js, it has no network dependencies and supports offline use. Users can install it with `dsh plugin add github:uckkk/dsh-tree`. Once installed, it can be invoked within a session, making it suitable for scenarios such as viewing directory structures.