dsh-pet-pill: Pet Medication Plugin

`dsh-pet-pill` is a pet medication-specific tool plugin for DeepSeek Harness. Maintained by uckkk and implemented purely in Node, it requires no network access and is used to query emergency pet care plans. It registers the `pet_pill` tool and requires the dependencies `@deepseek-ai/cordis` (^4.0.1) and `@deepseek-ai/dsh-tools` (>=0.1.0-rc.6). Users can install it with `dsh plugin add github:uckkk/dsh-pet-pill`, after which it can be invoked during a session. When using it, pay attention to permissions and review the source code.