dsh-pizza-size: Pizza Size Conversion Plugin

The `dsh-pizza-size` plugin for DeepSeek Harness (DSH) is a pure Node.js tool designed to provide local circular dimension calculations without network requests. It registers the `pizza_size` tool and supports precise area or circumference conversion based on specified parameters. Developers can install and enable the plugin with a simple command, integrating it into agent workflows to quickly handle size estimation tasks.