* backport useCommentsView from comments refactor
* adapt live comments and creation to useCommentsView; better outline conditions
* better deps usage, remove unused props
* safer usage of root and item
* light cleanup
* cleanup: remove unused useRoot on live comments
* light cleanup and affirm purpose of each function
* fallback to createdAt if no lastCommentAt only if we actually visit the item, not by default
* fix: don't track comments, remove unused useRoot, fix signature
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