opencodezen4dsh: The Free OpenCode Zen Model for DeepSeek Harness

The DeepSeek Harness (DSH) plugin `opencodezen4dsh` connects directly to OpenCode Zen’s free channel via a native adapter, enabling model access with zero credentials and zero setup. Based on a forked version, it supports streaming, image input, optional thinking levels, and a session log security fix. Installation requires downloading the `.tgz` package and adding it via CLI, with support for CLI impersonation and self-healing capabilities. Note that DSH ≥0.1.7 and Node.js ≥20 are required, and some models (such as `exo-free`) are blocked.