dsh-revdiff: DeepSeek Harness Interactive Diff Review Plugin

`dsh-revdiff` is a native interactive Git diff review plugin for DeepSeek Harness, designed to enable a closed-loop workflow of "modifying code - reviewing changes - providing feedback to the Agent". The plugin is released under the MIT license and requires a Node.js environment of ^22.19.0 or >=24.0.0. Its core functionality includes supporting interactive reviews of tracked, staged, or unstaged changes, allowing annotations such as issues, suggestions, questions, and praise to be added at the file and code-line level, and submitting structured review comments directly to the current Agent via `agent.followup()`. Users can invoke it with the `/revdiff` command and parameters such as `--staged`, paths