yinchao-ai-music: AI Music Generation Agent Skill

`yinchao-ai-music` is a DeepSeek Harness plugin that integrates AI music generation from the Yinchao Open Platform. It supports generating songs, BGM, and musical continuations from text, lyrics, or reference audio, and includes support for long-running tasks. Users can install it using the official commands, configure an API Key, and then invoke it in Harness with natural-language instructions to turn text into audio, making it suitable for content creation and other use cases.