fix game loop timer

src/ability.js

@@ -4,12 +4,16 @@ export default class Ability {
   id = crypto.randomUUID()
   name = 'Ability'
   cooldown = 0
-  effect = () => {}
   castTime = 0
 
+  #effect = () => {}
+
+  get effect() { return this.#effect }
+  set effect(value) { this.#effect = value }
+
   constructor(options) {
     if (options.name != null) { this.name = options.name }
-    if (options.effect != null) { this.effect = options.effect }
+    if (options.effect != null) { this.#effect = options.effect }
     if (options.cooldown != null) { this.cooldown = options.cooldown }
     if (options.castTime != null) { this.castTime = options.castTime }
   }