Notebook/home page for teachers

- Notebook (for teachers)
- No single place for a teacher to look at all annotations in a group (notebook)
- Should be able to easily search and filter across groups
- Some sort of analytics tool across groups (e.g. 10% of annotations on this sentence, engagement levels, top annotation - most replies?)

Eventually we will also want "institutional" dashboards that aggregate data from all courses at a school so the admin can see things like:
how many courses
how many students
etc

The issue proposes a teacher notebook or home page with cross-group annotation search, filtering and analytics, followed by institutional dashboards. No files, tests or entry points are named, so the first step is to identify the existing notebook, group and annotation areas. Done requires an agreed scope and concrete acceptance criteria for the teacher-facing work.

Written by the indexing model from the issue text.