dsh-cuid: CUID Generation Plugin

The dsh-cuid plugin provided by DeepSeek Harness (DSH) is a tool for generating CUIDs and belongs to the admin-security category. It is implemented in pure Node.js with no network dependencies and is primarily used to generate unique and stable IDs for agents or sessions. Users can install it by running `dsh plugin add github:uckkk/dsh-cuid`. Once installed, they can directly invoke its tool in the current session to generate CUIDs.