dsh-opendesigner: A Local-First React/Tailwind Visual Designer

The `dsh-opendesigner` plugin for DeepSeek Harness (DSH) provides developers with a local-first React and Tailwind visual editor, addressing the lack of design tooling in the DSH environment. It enables Agents or developers to manipulate design mockups directly on a constrained tool surface, supporting local editing, approval for destructive writes, and Mock mode. Installation requires Node 22.14+ and a Host restart, while overlays can be used to debug or preview designs. The plugin ensures security through path jails and approval channels, and prohibits API keys from being uploaded to the repository.