I assume Yii doesn’t already have something like this, so I’m planning on making a method that will wrap each error returned via $model->errors in <p></p> tags.
Where is the best place to put this? A custom helper file? If so, where should I place this file?
No, there’s no suggested place. There’s no need to add anything to autoload if you’re using sub-namespaces of already existing namespace such as “app\something” or “frontend\something”.