Is your feature request related to a problem? Please describe.
Using config v4 with typescript is causing issues because the types are not aligned.
Types are still on v3 so things like the rework of config.util are not present.

Describe the solution you'd like
Update @types/config to v4.

Describe alternatives you've considered
It's more work but could be nice for config to bring the types into the package itself. Or even more long term an eventual conversion to typescript.

Please tell us about your environment:

• node-config version: 4.2.0
• node-version: 24.12.0