dsh-tune-guide: Instrument Tuning and Practice Plan Generation

`dsh-tune-guide` is a local plugin for DeepSeek Harness (DSH), designed to provide agents with instrument tuning and practice plan generation capabilities. Implemented entirely in Node.js, it has no network request dependencies and is suitable for offline scenarios. By registering tools, it supports returning practice plans according to provided parameters. Installation requires specific dependencies to be met, making it well suited for integration into the DSH toolchain.