Hide or dim "Sign In" button when user is already authenticated

When a user is already signed in to Claude Code, the "Sign In" button remains fully visible and styled with a bright accent color — making it the most visually prominent element in the UI, even though it serves no active purpose for authenticated users.

Request: Either hide the button entirely when the user is already signed in, or render it in a muted/secondary style so it doesn't draw attention away from the actual chat interface.

Environment: VSCode extension, Windows 10