Module
One row per completed lesson; its presence is the mark.
The last saved position, in seconds, per learner and lesson.
The lesson location the learner opened last in each course; updatedAt orders them.
One row per lesson whose ticket the learner has earned; kept for good.
One row per module whose prize the learner has claimed; kept for good.
One row per course the learner has enrolled in; kept for good.
Every table that holds a learner's own data. Each cascades from user, so
deleting the user deletes them all; the account-deletion suite enumerates
this list to prove it.
The learner card: one per learner.