Reads the resolved configuration a scan run saved during its preparation step
(<output_dir>/shared/01-config_used.rds) and returns it as a list, for
the summary and reporting steps to use.
load_config_snapshot(output_dir)The resolved-configuration list saved by the run's preparation step.
Errors if the file is absent (the run's preparation step has not been run
yet). Cost is that of a single readRDS.