By: Tom Sydney Kerckhove <syd@cs-syd.eu>
mutationCheck: accept a pre-written 'configFile' alongside 'config' Lets the caller maintain the YAML config as a sibling file in their own repo (e.g. ./mutation.yaml) instead of expressing it inline as a Nix attrset. When 'configFile' is set, it is passed to the plugin verbatim and 'config' is ignored.