@openllmsh/dsh: Routing the DeepSeek Harness Through the OpenLLM Gateway

The DeepSeek Harness plugin `@openllmsh/dsh` is a pure configuration-layer plugin designed to route traffic to a local OpenLLM gateway. It is implemented through `cordis.patch.yml` and requires no runtime code. Core features include: 1. Adding an OpenLLM default model provider to the Harness, pointing to the local gateway; 2. Registering the OpenLLM MCP server. Before use, OpenLLM must be installed and the `openllmd` daemon must be running, and the host must meet the Node.js version requirements.