Update tokens and platform metadata (name, userId) for an existing connection.
Use this on reconnection so the stored channel name/id stays current.
When refreshToken is empty, the existing stored refresh token is left unchanged.
Returns public shape (no tokens) so callers never receive secrets.
Update tokens and platform metadata (name, userId) for an existing connection. Use this on reconnection so the stored channel name/id stays current. When
refreshTokenis empty, the existing stored refresh token is left unchanged. Returns public shape (no tokens) so callers never receive secrets.