dsh-shower-size: Shower Enclosure Size Calculator

The DeepSeek Harness (DSH) plugin `dsh-shower-size` is maintained by developer uckkk and is intended to provide precise shower enclosure dimension calculations for the DSH ecosystem. The plugin is implemented purely in Node.js, has no network dependencies, and is suitable for local environments. The installation command is `dsh plugin add github:uckkk/dsh-shower-size`; after installation, it can be directly invoked in a DSH session to perform calculations using the relevant tools.