Just pick a framework and make it work. It sounds like you should spend the bulk of your time instead on figuring out how the text annotation portion will work

Just pick a framework and make it work. It sounds like you should spend the bulk of your time instead on figuring out how the text annotation portion will work - the framework will be secondary or even tertiary to being able to annotate the text and saving and retrieving the annotations. Copy a lot from the other websites, ex: medium.com does this annotation, yeah? (side question, why not blog on medium and leverage the annotations there?)