[BUG] Proxy configuration of NPM not used when downloading .jar via version manager

🐛 Bug Report:

Describe the bug

I develop behind a corporate proxy and thus have to set https-proxy and proxy in NPM in order to download @openapitools/openapi-generator-cli from the official NPM registry.
This works without any issue, however when the CLI tries to download the required .jar file from Maven Central, I get a proxy error because the proxy is not respected when downloading the .jar itself.

I was able to "fix" this setting the HTTP_PROXY and HTTPS_PROXY variables on system level.
However this in an inconvenient solution as I have to set it twice.

It would be great if the CLI would respect the configured npm for downloading the .jar file.

Steps to Reproduce

Steps to reproduce the behavior:

1. Only set https-proxy and proxy using .npmrc
2. Try running openapi-generator-cli generate
3. See error that .jar file cannot be downloaded

Expected behavior

.jar file download should work with only setting the NPM proxy configuration.

Operation System (please complete the following information):

• Windows 11

Package System (please complete the following information):

• npm 11.62
• Node 24.11.1

Additional context

Add any other context about the problem here.