dsh-fx-convert: FX Conversion Plugin

The `dsh-fx-convert` plugin for DeepSeek Harness (DSH) provides local currency conversion and performs precise calculations without requiring network access. Maintained by uckkk, it supports offline use and environments with restricted network requests. Installation requires specific dependencies, and the registered tool name is `fx_convert`. Users should review the source code and license to ensure compliance with their environment’s permission requirements.