dsh-iceland: Iceland Country Plugin

The DeepSeek Harness plugin dsh-iceland is a “Iceland nation” plugin implemented purely in Node.js. It features a core with no network dependencies, integrates through the Cordis patch mechanism, and runs locally without generating network traffic. The plugin depends on @deepseek-ai/cordis and @deepseek-ai/dsh-tools, runs with the permissions of the current process, and is suitable for building offline agent components.