feat(api): let wounded monsters turn aggressive

apps/api/src/monsters/monster-abilities.ts

@@ -38,10 +38,21 @@ export interface MonsterGuardAbility {
   durationRounds: number;
 }
 
+export interface MonsterEnrageAbility {
+  /**
+   * Once its HP first falls to or below this share of maximum, the monster
+   * hits harder for the rest of the fight. One deterministic state change,
+   * never reversed and never rolled (Playable Slice 0.10 §5).
+   */
+  hpThresholdPercent: number;
+  damageMultiplier: number;
+}
+
 export interface MonsterAbilities {
   telegraph?: MonsterTelegraphAbility;
   bleed?: MonsterBleedAbility;
   guard?: MonsterGuardAbility;
+  enrage?: MonsterEnrageAbility;
 }
 
 export const NO_MONSTER_ABILITIES: MonsterAbilities = {};