dsh-exposure-calc: DSH Exposure Portfolio Calculation Plugin

The DeepSeek Harness (DSH) plugin `dsh-exposure-calc` provides local exposure portfolio calculations without requiring network requests. Maintained by uckkk, the plugin registers the `exposure_calc` tool upon installation, supporting precise parameter-based calculations and returning the results. Built with pure Node.js, it relies on `@deepseek-ai/cordis` and `@deepseek-ai/dsh-tools`. Listed in the community directory with no official affiliation, it is ideal for scenarios requiring fast, local calculation results.