dsh-hp2kw: Horsepower to Kilowatt Plugin

The DSH plugin `dsh-hp2kw` is designed to address physical unit conversion needs by converting horsepower values to kilowatts. It is maintained by istone, implemented in pure Node.js, requires no external network access at runtime, and is lightweight and dependency-free. After installation using the official command, the plugin takes effect automatically when the DSH process starts. Developers should pay attention to the required environment and dependency requirements, and are advised to review the source code and license before use.