DeepSeek Harness Plugin: Geodetic Toolbox

The `dsh-geodesy` plugin eliminates common large-model errors in spherical geometry calculations by executing them locally, providing precise geodesic solutions for Earth's surface geometry. It includes seven core functions covering great-circle distance, azimuth, rhumb lines, track intersections, and spherical area calculation, supports parsing multiple coordinate formats, and defaults to the IUGG mean Earth radius. Users must install and configure it via pnpm; once installed, it is invoked automatically in DeepSeek Harness, ensuring high accuracy and stability in ge calculations.