The [Gitea VS Code extension](https://gitea.com/gitea/gitea-vscode)
currently signs in through the builtin `tea` OAuth2 application. Gitea
keeps one grant per user and application, so anyone who has already
signed in with the tea CLI gets `a grant exists with different scope`
when the extension requests its own scopes, and sign-in fails
(gitea/gitea-vscode#24).
This adds a dedicated builtin application for the extension, following
the same mechanism as the existing CLI entries: