Get Config

Retrieve application configuration settings.

Returns different configuration based on authentication status:

• Authenticated users: Full ConfigResponse with all settings
• Unauthenticated users: PublicConfigResponse with limited, safe-to-expose settings

Args: user: The authenticated user, or None if unauthenticated.

Returns: ConfigResponse | PublicConfigResponse: Configuration settings appropriate for the user's auth status.

Raises: HTTPException: If an error occurs while retrieving the configuration.