dsh-plugin-dev: Local Plugin Development Management Panel

`dsh-plugin-dev` is a local plugin development plugin for DeepSeek Harness (DSH) designed to simplify the installation of local plugins via `file:` or `link:`. It scans `package.json` files in development directories and provides a web management panel that allows users to add or remove plugins, open source directories, and continue development. In addition, the plugin includes a secure confirmation session that lets users manually prefill and confirm actions such as creating, updating, and managing GitHub repository discussions, instead of automatically executing high-risk commands, thereby ensuring safe operations. After installation, users must restart DSH and hard-refresh the page.