dsh-workspace-git: Create a DeepSeek Harness Workspace Directly from a Git URL

`dsh-workspace-git` is a plugin for DeepSeek Harness (DSH) that simplifies workspace creation through a web interface by integrating Git repository cloning directly, replacing cumbersome manual `git clone` operations. The plugin supports secure execution, interactive control, and credential support. Users must install the specified version and restart the service. After installation, DSH provides two options: using an existing folder or cloning a Git repository. Configuration options include timeout duration and output limits; users should note pnpm 10 compatibility settings and security notices.