feat(武器系统): 添加魔法导弹武器及配套子弹逻辑

实现魔法导弹武器系统，包括：
1. 新增HOLD_LOOP发射类型武器
2. 添加魔法导弹子弹类实现追踪和分裂逻辑
3. 修改武器基类支持循环攻击模式
4. 更新角色控制器支持新武器类型
5. 添加相关资源文件和配置

scripts/Structs/Weapon.gd

@@ -6,7 +6,7 @@ enum EmitType {
 	HOLD_SHOOT,
 	CLICK_SHOOT,
 	CHARGE,
-	HOLD_ONCE
+	HOLD_LOOP
 }
 
 @export var avatarTexture: Texture2D = null
@@ -49,6 +49,7 @@ var cooldownTimer: CooldownTimer = null
 var originalStore: Dictionary = {}
 var chargedTime: float = 0
 var attackSpeed: float = 1
+var looping: bool = false
 
 func _ready():
 	cooldownTimer = CooldownTimer.new()
@@ -188,19 +189,41 @@ func canAttackBy(entity: EntityBase):
 	cooldownTimer.speedScale = entity.fields.get(FieldStore.Entity.ATTACK_SPEED) * attackSpeed
 	return cooldownTimer.isCooldowned() and entity.isEnergyEnough(needEnergy) and checkAttack(entity)
 func tryAttack(entity: EntityBase):
-	if canAttackBy(entity):
-		var result = await attack(entity)
-		if result:
-			cooldownTimer.start()
-			entity.useEnergy(needEnergy)
-		return result
+	if looping:
+		if checkAttack(entity):
+			return await attack(entity)
+		else:
+			exitLoop(entity)
+	else:
+		if canAttackBy(entity):
+			if emitType == EmitType.HOLD_LOOP:
+				var result = await loopStart(entity)
+				if result:
+					looping = true
+					cooldownTimer.start()
+					entity.useEnergy(needEnergy)
+				return result
+			else:
+				var result = await attack(entity)
+				if result:
+					cooldownTimer.start()
+					entity.useEnergy(needEnergy)
+				return result
 func charged(base: float, percent: float):
 	return base * sqrt(1 + chargedTime / 15 * percent)
+func exitLoop(entity: EntityBase):
+	if !looping: return
+	looping = false
+	loopExit(entity)
 
 # 抽象
 func update(_to: int, origin: Dictionary, _entity: EntityBase):
 	return origin
+func loopStart(_entity: EntityBase):
+	pass
 func checkAttack(_entity: EntityBase) -> bool:
 	return true
 func attack(_entity: EntityBase):
 	pass
+func loopExit(_entity: EntityBase):
+	pass