dsh-percentage: A Pure Node.js Percentage Calculation Plugin

The `dsh-percentage` plugin in the DSH ecosystem is designed to address the pain point of calculating percentages locally in agents, providing lightweight computation with no network dependency. Built on pure Node.js, it can execute calculations locally without requiring external APIs. Users must install it via the official command and configure bundles in their profile. Because the plugin executes third-party code with process-level privileges, review the source code before installation.