Missing documentation: corporate proxy and enterprise certificate configuration for GHE environments

Environment

• OS: Windows 11 Enterprise (corp-managed)
• VS Code: latest
• Extension: github.vscode-pull-request-github (latest)
• GitHub Enterprise Server or GitHub Enterprise Cloud

Description

The extension README and VS Code Marketplace page contain no documentation about how to configure the extension in corporate environments. Common enterprise setup requirements that are undocumented:

1. Custom CA certificates — GHE instances often serve TLS certs signed by an internal CA. There is no guidance on using NODE_EXTRA_CA_CERTS or VS Code's http.systemCertificates setting with this extension.
2. Proxy configuration — It is unclear whether the extension respects http.proxy in VS Code settings, HTTPS_PROXY env vars, or both. No troubleshooting guidance exists for ECONNREFUSED/CERT_UNTRUSTED errors on proxied networks.
3. GHE SSL verification bypass for dev/staging — Some orgs use self-signed certs on non-prod GHE; the only workaround users currently find is NODE_TLS_REJECT_UNAUTHORIZED=0 which is unsafe.
4. SSO token scope requirements — SAML-enforced organizations require PATs to be SSO-authorized; the extension does not guide users through this, leading to cryptic 403 errors.

Expected vs Actual Behavior

Expected: Wiki or README section covering: proxy settings, custom CA trust, SSO authorization steps, and known limitations for air-gapped GHE deployments.

Actual: No enterprise/corp configuration documentation exists; users must rely on community workarounds and trial-and-error.

Additional Context

This is a documentation gap, not a bug. A single 'Corporate / Enterprise Setup' section in the README would reduce a significant class of support requests from enterprise users.