dsh-round: Rounding

The `dsh-round` plugin for DeepSeek Harness (DSH) follows the “everything is a plugin” philosophy, providing a lightweight numeric rounding function. It requires no network requests and is suitable for local integration. Maintained by istone and implemented in pure Node.js, the plugin registers a tool for invocation in the session after installation. The installation command is `dsh plugin add github:uckkk/dsh-round`. To use it, the dependencies `@deepseek-ai/cordis` (^4.0.1) and `@deepseek-ai/dsh-tools` (>=0.1.0-rc.6) are required, and it runs with the permissions of the current process.