dsh-fish-weather: Fishing Weather Assessment

`dsh-fish-weather` is a DeepSeek Harness fishing weather assessment plugin implemented entirely in Node.js. It depends on `@deepseek-ai/cordis` and `@deepseek-ai/dsh-tools`, and provides the ability to output practical fishing plans without network dependencies. Users can install it via a command and invoke it directly in a conversation to obtain weather assessment logic, making it suitable for deployment scenarios with network restrictions or a need to reduce external dependencies. Before use, the source code should be inspected to ensure safety.