dsh-mcp-manage: MCP Management Plugin for the DeepSeek Harness Web GUI

`dsh-mcp-manage` is a Web GUI plugin for DeepSeek Harness (DSH) that provides immediate management of MCP tools without restarting the host. Core features include viewing installed tools, adding and editing server configurations (supporting stdio/streamable-http), enabling or disabling with one click, uninstalling instances, and managing composite configurations. All states are persisted in local files, and operation failures are visible. Users can install it via a command and use it on the Settings page. It supports DSH version ≥ 0.1.0-rc.6.