dsh-kph2mph: km/h to mph

The DeepSeek Harness (DSH) plugin `dsh-kph2mph` is designed for speed unit conversion needs in agent development. Maintained by `uckkk`, it focuses on purely numeric conversion between kilometers per hour and miles per hour. As a lightweight tool with no network dependencies, its core features include unit conversion and a pure Node.js implementation. The installation command is `dsh plugin add github:uckkk/dsh-kph2mph`, and it requires environment dependencies such as `@deepseek-ai/cordis` and `@deepseek-ai/dsh-tools`. Since the plugin runs with the current process permissions, users are advised to review the source code before installation to verify its security.