dsh-interior-clean: Interior Cleaning Tool

`dsh-interior-clean` is a local workflow plugin for DeepSeek Harness (DSH), focused on vehicle interior maintenance scenarios. It receives parameters through the `interior_clean` tool, performs precise calculations locally, and generates cleaning recommendations without relying on external APIs. The plugin is implemented in pure Node.js, features zero network dependencies, and requires installing `@deepseek-ai/cordis` (^4.0.1) and `@deepseek-ai/dsh-tools` (>=0.1.0-rc.6). It is recommended to review the source code before use. The project is released under the MIT license.