dsh-kn2km: Knots to Kilometers per Hour

The DeepSeek Harness (DSH) plugin `dsh-kn2km` provides local conversion between knots (nautical miles per hour) and kilometers per hour without any network dependency. Maintained by uckkk and licensed under MIT, it supports a pure Node.js implementation. Users can install it with `dsh plugin add github:uckkk/dsh-kn2km`, making it suitable for speed unit calculations in offline environments.