dsh-midpoint: Midpoint Calculation

The DeepSeek Harness (DSH) plugin `dsh-midpoint` is designed to extend local computing capabilities, enabling developers to perform midpoint calculations in offline environments. Maintained by the developer `uckkk`, it is implemented in pure Node.js with no network dependencies. To install it, run `dsh plugin add github:uckkk/dsh-midpoint`. After installation, the relevant tools will be registered in the current session and can be invoked directly. Because the plugin runs with the permissions of the current DSH process and is an open-source project under the MIT license, it is recommended to review the source code and license before use.