Introducing the robbywang25/dsh-llm-mlx Plugin

The `robbywang25/dsh-llm-mlx` plugin is a local model adapter for DeepSeek Harness (DSH), designed specifically for Apple Silicon macOS. It connects local MLX-LM or MLX-VLM models to DSH via an OpenAI-compatible interface, offering two operating modes: hosted mode (where DSH manages the process) and reuse mode (connecting to an existing server). The plugin must be used with a specific version of DSH, requires Python and the corresponding MLX libraries to be installed, and does not include model weight files.