Plugin update fails with "no source information" for GitHub-installed plugins #1290

Describe the bug

Plugins installed from a GitHub repository using /plugin install owner/repo:plugin-name don't store source information, causing /plugin update to fail with "has no source information and cannot be updated".

Affected version

GitHub Copilot CLI 0.0.402

Steps to reproduce the behavior

1. Install a plugin from GitHub: /plugin install ViktorHofer/skills:msbuild-skills
2. Verify installation: /plugin list shows msbuild-skills v1.1.0
3. Try to update: /plugin update msbuild-skills
4. See error: Failed to update plugin: Plugin "msbuild-skills" has no source information and cannot be updated

Expected behavior

Plugins installed from GitHub should store the source repository information so that /plugin update can fetch the latest version.

Additional context

• OS: Windows
• Shell: PowerShell
• The only workaround is to uninstall and reinstall the plugin