dsh-query-string: Query String ↔ Object Conversion

dsh-query-string is a query string processing plugin dedicated to DeepSeek Harness (DSH). Built in pure Node.js, it supports mutual conversion between URL query parameter strings and objects, providing localized data parsing capabilities. It can be installed via `dsh plugin add` and enabled by configuration in `package.json`. As a locally executed tool, it requires no network interaction, though users are advised to review the source code on their own. The plugin is designed to simplify data processing in agent development.