s&box: Correct damage pipeline order — pre-event, armour, health, OnDeath, then Kill()

Developers implementing a damage system in s&box often miss the correct ordering: the pre-damage event must fire before any stat modification (so listeners can cancel or modify damage), armour must absorb before health is reduced, and GameManager.OnDeath must be called before Health = 0 — otherwise kill-feed and stat tracking fire with stale health values.