dsh-camp-site: Campsite Selection Tool

The `dsh-camp-site` plugin for DeepSeek Harness (DSH) is designed to meet campsite selection requirements in specific vertical scenarios. Implemented purely in Node with no network dependencies, it returns practical camping plans based on provided parameters. Users can install it via a command and invoke the relevant tools in DSH sessions. Before installation, ensure the environment satisfies the required peerDependencies and be aware that it runs with the permissions of the current process.