dsh-wolfram: Invoke Wolfram Mathematica in DeepSeek Harness

`dsh-wolfram` is a lightweight community plugin for the DeepSeek Harness (DSH) environment, designed to enable agents to directly invoke local Wolfram Mathematica or Wolfram Engine to perform mathematical computations. By encapsulating the local `wolframscript` command and registering it as a tool named `wolfram`, the plugin allows agents to pass Mathematica expressions as parameters, automatically capturing and returning standard output results, without requiring developers to manually maintain process invocation and result parsing logic. Its core advantage lies in its zero npm dependencies, utilizing only the Node.js built-in `child_process` module, which maintains extremely low resource overhead. Users are required to ensure that Wolfram Mathematica or Wolfram Engine is installed locally.