DeepSeek Harness Plugin: dsh-rest-time (Rest Time Between Sets Calculation)

`dsh-rest-time` is a pure Node.js plugin designed specifically for DeepSeek Harness to automatically and accurately calculate inter-group rest periods within workflows. It has no network dependencies, can be added via an install command, and depends on the `@deepseek-ai/cordis` and `@deepseek-ai/dsh-tools` environments. It runs with the current process permissions, so its permission scope should be carefully considered. It is well suited to local workflows, where detailed calculation results can be obtained by invoking the registered tool.