dsh-model-pro: Full Lifecycle Management for the llm-pi-ai Provider

`dsh-model-pro` is a dynamic Cordis plugin for DeepSeek Harness (DSH) that provides a visual full-lifecycle management UI for the `llm-pi-ai` provider. It supports provider CRUD, encrypted API key storage, remote model discovery, connectivity testing, intelligent routing (with seamless fallback), and provider composition. After installation, users can create, configure, and test models through the Web GUI and use the observability dashboard to monitor health status and logs, addressing the cumbersome management of multi-model invocation chains.