dsh-ip: Validate/Classify IP Addresses and Calculate IPv4 CIDR Ranges

dsh-ip is a Node.js-based DeepSeek Harness (DSH) plugin designed to simplify network logic processing in agent workflows. It provides `ip_info` for IP validation and classification, and `cidr_range` for calculating IPv4 network ranges. Users need to install it using `dsh plugin add` and enable it in the profile's `package.json`. The plugin runs locally, so users should be cautious about the security of third-party code when using it.