dsh-current-calc: DeepSeek Harness Current Calculation Plugin

The `dsh-current-calc` plugin for DeepSeek Harness (DSH) is designed to provide agents with precise current-calculation capabilities that do not depend on the network. Built on the Cordis protocol, it performs local calculations by registering the `current_calc` tool. Users must install it via the official command, after which it can be invoked directly within a session. The plugin is implemented entirely in Node and runs locally; note that it operates with the current process's permissions, so it is recommended to review the source code and license before installation.