dsh-plugin-muapi: Integrating MuApi generative models into DeepSeek Harness

`dsh-plugin-mui` is a DeepSeek Harness (DSH) plugin maintained by SamurAIGPT and released under the MIT license. By registering the `muapi_generate` tool, it encapsulates over 100 image, video, and audio generation models from the MuApi platform into DSH agents, simplifying the development of glue code for authentication, task submission, result polling, and output URL retrieval. The plugin workflow involves submitting a generation task to the MuApi API, polling for results at configured intervals, and finally returning the output URL. Key configuration items include the enabled status, API Key environment variable reference, base URL, polling interval, and timeout (default 600 seconds). Users need to use `dsh plugin ad...`