dsh-music-tui: Controlling YesPlayMusic in dsh-TUI

`dsh-music-tui` is a plugin for DeepSeek Harness TUI that displays playback status and controls playback through a command interface and a top music bar while YesPlayMusic TUI is running, without interrupting the terminal flow. It provides a `/music` command family for showing, hiding, toggling playback, and skipping tracks, and supports Kitty true graphics, four spectrum styles, and fallback for rich status views. Installation requires Node.js ^22.19 or >=24 and the corresponding version of dsh-TUI. The plugin is controlled via a public CLI, hides the music bar by default, and can be managed through configuration files.