- Add LevelUpSession model (DRAFT state, soft-archive on commit via committedAt)
- Add LevelUpHistory model (append-only audit log of committed level-ups)
- Add ClassProgression model (per-class, per-level grants and prof changes)
- Add ClassFeatureOption model (sub-choices like doctrines/schools/instincts)
- Extend Character with freeArchetype Boolean (D-08) and prereqViolations Json (D-06)
- Add reverse relations levelUpSessions and levelUpHistories on Character
- Schema formatted via prisma format and validated via prisma validate