fix: record control driven cast cancellations (#16)

src/game/combatEvents.ts

@@ -18,6 +18,8 @@ export interface StructuredCombatEvent {
   readonly sourceActorId: string;
   readonly targetActorId: string;
   readonly abilityId?: string;
+  /** Source ability that caused an interruption; abilityId remains the canceled cast. */
+  readonly causeAbilityId?: string;
   readonly school?: DamageSchool;
   readonly rawAmount: number;
   readonly effectiveAmount: number;