dsh-text-diff: Line-Level Text Diff Plugin

`dsh-text-diff` is a plugin for DeepSeek Harness that provides local line-level text diff functionality. The tool is implemented in Node.js and requires no network requests or external services, ensuring privacy and secure offline operation. Developers can install it via the official command and enable it in their profile configuration. Once enabled, they can directly invoke the registered tool to perform precise line-by-line text comparison. Because the tool involves running third-party code locally, it is recommended to carefully review its source code and license before installing.