- Add 'github-copilot' to LlmProviderFlavor type in settings dialog
- Add GitHub Copilot Student to moreProviders array in UI
- Add github-copilot to initial providerConfigs state
- Add isGitHubCopilot flag to handle Device Flow auth flow
- Add GitHub Copilot authentication button in settings UI
- Add GitHub Copilot models (6 models) to listOnboardingModels() output
- Add eslint-disable comment for mock fetch in tests
This fixes the issue where GitHub Copilot Student was not appearing in the Models dropdown in the Settings dialog.
