Get Student Progression

Skill + theme mastery for the authenticated student's dashboard.

Returns an empty payload with readiness.is_ready false — and does no work — for a student who hasn't submitted enough exercises yet (EXC-451); the frontend shows the "keep practising" state in that case.

Otherwise may generate (and persist) v2 evaluations on the fly for first submissions that don't have one yet — the same cold-start routine the error-analysis endpoint uses — so the first call after a stretch of activity can take longer; subsequent calls reuse the persisted evaluations.