Problem

Netclaw PR #1509 adds GitHub Enterprise support for GitHub Copilot provider authentication. That is the only behavior this documentation issue should cover.

Implementation PR: netclaw-dev/netclaw#1509
Related product issue: netclaw-dev/netclaw#1456
Prior superseded PR with early screenshots/context: netclaw-dev/netclaw#1491

Scope

Document how operators configure the github-copilot provider to authenticate against GitHub Enterprise / GitHub Enterprise Server.

The docs should explain the behavior from PR #1509:

• Public GitHub Copilot keeps the default github.com auth endpoints unless Enterprise values are explicitly configured.
• GitHub Enterprise auth is configured through provider vendor options, including GitHubHost and GitHubApiBase.
• Device OAuth, OAuth refresh, and Copilot token exchange use the configured GitHub Enterprise auth host/API base.
• Copilot chat/model traffic remains controlled by the provider endpoint.
• Operators should understand which value controls auth host/API behavior versus model endpoint behavior.

Out of scope

Do not document this as generic GitHub Enterprise setup. This issue is not about:

• GitHub Issues or PR tooling.
• GitHub webhooks.
• Generic GitHub CLI setup.
• gh auth login, unless PR #1509 actually depends on gh for github-copilot provider auth.
• A new TUI feature request. Include TUI instructions/screenshots only if the provider-auth configuration already exists in the implemented flow.

Acceptance criteria

• Website docs explain GitHub Enterprise auth for the github-copilot provider only.
• Docs name and define the relevant provider vendor options, especially GitHubHost and GitHubApiBase.
• Docs distinguish GitHub Enterprise auth endpoints from the Copilot chat/model provider endpoint.
• Docs include setup and verification steps grounded in Netclaw behavior from PR #1509.
• Troubleshooting covers wrong host/API base, OAuth/device-code failures, refresh failures, and Copilot token exchange failures.
• Docs avoid generic gh auth guidance unless it is proven to be part of this provider-auth flow.