- dealDamage returns new Character instead of mutating in-place
- SelfDamageForbidden uses reference equality (this === target)
- Negative damage throws at the boundary
- Removed duplicate Health.maxHealthForLevel (Level.ts is source of truth)
- Allium spec uses max(0, ...) for health floor precision
- New property: NegativeDamageForbidden (11 total properties)
- Allium spec: damage-and-health.allium
- 5 fast-check properties: damage reduces health, health non-negative,
death at zero, self-damage forbidden, dead cannot take damage
- Character.createWithHealth factory for testing with arbitrary health
- Character.dealDamage(target, damage) method
- Level value object (1..10, level-capped health)
- Health value object (non-negative, pure sub/add)
- Status discriminated union (alive | dead)
- Character entity with private constructor and static factory
- 9 fast-check properties covering creation invariants
- Allium spec with entities, rules, and invariants
