Let visitors post comments on category page

Short answer: No, it is impossible, if we are talking about WP way, because it was not provided by WP architecture.

It could be done if you create your own plugin (or implement it as a part of theme). To do it you need to create custom table and implement logic for saving comments and displaying comments.

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