After changing the site root, how to reflect this for wp-admin too?

You should be able to regex it with /wp/(wp-admin/.*) and point that to /$1, thus removing the /wp/. You can do this either via .htaccess or via wordpress’ rewrite API.

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