This is probably solvable with Hypothesis and a custom browser extension. More generally, third-party annotation of web (especially hypertext) resources is an

This is probably solvable with Hypothesis and a custom browser extension. More generally, third-party annotation of web (especially hypertext) resources is an underexplored opportunity. I suspect it’s at least partly because integration isn’t a first-class concern for these sorts of apps (if it were, they’d build it themselves and own the feature and the data), so the experience isn’t that great and the marketing is significantly diluted.