Without this call, settings from the global Nix configuration are never
loaded, leaving readOnlyMode = true (the default). This prevents Nix
from adding paths to the store during evaluation, causing errors like:
error: path '/some/local/path' does not exist
This fix loads global settings before creating the EvalState, enabling
path coercion for local file references.
The previous "See underlying function" text didn't provide a way to
find the underlying function, forcing users to search the codebase.
Stating the safety contracts explicitly makes the API usable.
