Let DeepSeek Harness search for and install community plugins on its own with dsh-find-plugins

`dsh-find-plugins` is a DSH skill plugin maintained by Nagi-ovo, licensed under BSD-3-Clause. When you ask the agent "Are there any plugins that can...", it will find public candidates from GitHub's `dsh-plugin` topic, judge the installation methods of bundle, Cordis and skill, report the required permissions first before installing and verifying the mounting after selecting one. The directory page command is: `dsh plugin add github:Nagi-ovo/dsh-find-plugins`. The plugin runs with the permissions of the current dsh process.