Library → Notes (/notes). Lists the learner's latest notes, pinned
first and then most recently edited, with a search over the titles,
content and tags of all of them (run on the server: the list holds only
the latest). /notes?topicId=<id> narrows the list and the search to one
topic; the lesson's notes action links there. Each row opens the note
(/notes/:noteId), where it can be edited, pinned or deleted; "New Note"
opens the editor (/notes/new, linked to the topic when the list is
filtered).