Show overlay upon player death

src/engine/simulation/simulation.ts

@@ -134,5 +134,10 @@ export function stepUntilPlayerTurn(w: World, playerId: EntityId): { awaitingPla
 
     const action = decideEnemyAction(w, actor, player);
     events.push(...applyAction(w, actor.id, action));
+
+    // Check if player was killed by this action
+    if (!w.actors.has(playerId)) {
+      return { awaitingPlayerId: null as any, events };
+    }
   }
 }