why can't add Header to global env?

### Describe the feature

I don't think I need a global variable setting, I just need a global header setting, and it is independent for each user. eolinker is easy to use because of this function.

### Environment

- 版本: 0.5.1
- Electron: 22.1.0
- Chromium: 108.0.5359.179
- Node.js: 16.17.1
- V8: 10.8.168.25-electron.0
- OS: Windows_NT x64 10.0.22621
- 平台: Electron

The issue describes a per-user global header setting for the API tool and reports an Electron environment, but names no files, tests, or entry points. First map how global environment variables are stored and applied, then define the header behavior and verify it independently for each user.

Written by the indexing model from the issue text.