DeepSeek Harness Heat Index Plugin

The DeepSeek Harness (DSH) plugin `dsh-heat-index` is designed to provide local heat index calculations. It is implemented entirely in Node.js, requires no network dependencies, and supports precise calculation based on temperature and humidity parameters. Developers can install it using the `dsh plugin add` command for use in restricted network environments. It relies on no external APIs, runs with DSH process permissions, and adds lightweight computational capabilities to the DSH ecosystem.