dsh-settings-params: Centralized Management of Environment Variables and Hot Reload Plugin

`dsh-settings-params` is a DeepSeek Harness (DSH) plugin designed to address the issues of cumbersome environment variable management and plugin configurations not taking effect after a restart. It supports centralized management of YAML variables, persistence to disk, and hot reloading of specific plugins through a whitelist mechanism. To use it, enable it in the web sidebar, explicitly authorize the model to read variables via the `expose` list, and select the plugins that require hot reloading (e.g., `dsh-sql`). The configuration file is located at `~/.dsh/.dsh-settings-params/params.yml`. After installation, the host process must be restarted. Be aware that once sensitive data is authorized, it may be included in session logs, posing a security risk.