How to show post title in content editor in backend?

$id isn’t set anywhere in your code snippet. get_the_title( null ); returns an empty string. If you want the title of a post, you’ll need to set $id to a proper post ID.

(Also, $args) is unset in the code you’ve posted, and I don’t see anywhere that you use query_contents either.)

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)