21st-dev/codex-plugin ? reverse-engineered prompt

Build me a Codex plugin for 21st.dev that lets me find and install React components, explore and improve a project specific UI, and create editable product videos from inside the coding agent.

I want it to connect to the 21st MCP server, ask me to sign in when I install it, and then open the editor in a separate browser view so I can keep editing the same project. It should support the component workflow and the video workflow, including creating a project, uploading assets, checking frames, trying variants, and exporting the final video.

Please make it work as a self hosted marketplace package I can add locally or from the repo, and keep the plugin setup clean so it can be tested from the CLI or desktop app. If anything depends on current plugin or MCP docs, look those up online and follow the latest approach.