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I've actually seen folks post a wiki-style list here of tools in the spirit of your request.
The key thing your post is missing is that the word you're looking for is "annotations".
https://hn.algolia.com/?q=annotations
Yes. Only one solving the problem very very well right now.
Memex - https://getmemex.com
More generally the open annotations standard is meant to address this use case. Older, now obselete tools like hypothes.is, and peerlibrary* laid a lot of the groundwork.
https://github.com/peerlibrary/peerlibrary