xby-pet-detect: Pet Emotion Recognition Plugin

The DeepSeek Harness plugin `xby-pet-detect` focuses on pet facial expression recognition, converting images into four emotion categories: Angry, Happy, Relaxed, and Sad. The plugin supports installation from GitHub or a local path and provides three interfaces: link input, Base64 encoding, and local file path. Before use, register on the XBY official website to obtain an API key, then set it in the DSH environment via `set_xby_apikey`. This plugin is released under the MIT license and is not officially affiliated with DeepSeek.