tools_manager: Add a tool switch for DSH

The plugin `zingreqe/tools_manager` provides sidebar tool management for DeepSeek Harness, allowing users to toggle built-in and mounted third-party tools one by one. Disabling these tools prevents them from being written to the context, thereby reducing per-round input token consumption. It also features a system prompt rewriting function, enabling users to customize the persona in chat mode or leave it blank to generate prompts based on the current tools. Changes to the switches take effect immediately for active sessions, and the plugin includes source labeling, Chinese descriptions, search functionality, and authorization prompts before web_ tool calls in chat mode. The npm package is `dsh-tools-manager`, version 1.0.4, under the MIT license. It requires Node.js >= 22, and DSH must be restarted after installation. It is suitable for DSH users who need to trim tool declarations based on tasks or control token usage. The plugin runs with the current DSH process permissions; users should check the source code and license before installing.