save_post action doesn’t passing post id to my function as argument

die is an alias of exit and from php.net:

void exit ([ string $status ] )

If status is an integer, that value will be used as the exit status
and not printed.

Try doing the following instead.

function psd_upload_kaydet($post_id)
{
    echo $post_id;
    die(); // for debugging, i'll explain it
}

edit.