dsh-git-tools: DeepSeek Harness Local Git Toolkit

`dsh-git-tools` is a plugin for DeepSeek Harness (DSH) designed to address security and latency issues when agents operate on local code repositories during a session. It provides four tools—`git_status`, `git_diff`, `git_log`, and `git_commit`—that allow agents to run Git commands directly on the host. Core features include checking branch status, viewing changes (with support for a statistics summary or a patch), listing commit history, and creating commits. The tools are executed securely via `execFile`, with controlled parameter injection and no destructive operations. Users only need to ensure Git is installed in their environment, then installation and usage can be completed through commands.