dsh-posture: Sitting Posture for Holding a Pen

The `dsh-posture` plugin for DeepSeek Harness (DSH), maintained by user `uckkk`, is a pure Node implementation of a fun dress-up-style tool. It has no network dependency, and its core function is to return calligraphy learning plans and guidance on pen grip and sitting posture based on specified parameters. Users can install it by running a specified command. It depends on the `@deepseek-ai/cordis` and `@deepseek-ai/dsh-tools` environments and is suitable for scenarios that require integrating calligraphy teaching content.