dsh-codex-compatible-pet: Codex-Style Desktop Pet for DeepSeek Harness

`dsh-codex-compatible-pet` is a DeepSeek Harness plugin that provides visual feedback on agent status through a Codex-style desktop pet. The pet automatically switches animations based on agent states such as running, waiting, and reviewing. The plugin supports sprite image formats, includes built-in Codex assets, and allows importing local custom pets. Users can click to interact, drag to reposition, or view a details card, and all settings are persistently saved. As a display-only plugin, it does not affect core logic and is designed to help developers monitor agent behavior intuitively.