dsh-jetlag: Jet Lag Adjustment

`dsh-jetlag` is a pure Node.js plugin for DeepSeek Harness (DSH) that provides jet-lag adjustment functionality without network dependencies. It is installed via the official command and depends on `@deepseek-ai/cordis` and `@deepseek-ai/dsh-tools`. The plugin is designed to address timezone calculation issues in scenarios such as travel planning and is open-sourced under the MIT License.