dsh-lithium: A Localized Lithium Element Data Query Plugin

`dsh-lithium` is a localized plugin for DeepSeek Harness (DSH) that provides standardized chemical data for lithium without requiring network access. The tool supports one-click retrieval of complete fields—including element name, atomic number, and electron configuration—or on-demand extraction of specific individual fields. It is designed to address data-fetching latency and network dependency issues in agent workflows. Developers can install it via the official command and directly invoke the `element_info` or `element_field` tools within their workflows to simplify data processing logic.