dsh-china: Chinese National Data Query Plugin

dsh-china is a DeepSeek Harness (DSH) plugin maintained by uckkk, designed to address the tedious issue of manually maintaining basic data related to China in agent development. The plugin is implemented purely in Node.js, has no network dependencies, and can run in offline environments. It provides two core capabilities: `country_info`, which returns a complete national information profile for China, and `country_field`, which supports querying specific data by field name. Before use, the specified versions of Cordis and DSH Tools must be installed. The installation command is `dsh plugin add github:uckkk/dsh-china`. By providing standardized local data, the plugin effectively simplifies the agent development workflow.