feat(人物): 添加熊角色及其攻击逻辑

- 在EntityBase中修改findWeaponAnchor方法以支持空节点检查
- 实现熊角色的注册、生成和AI行为
- 添加熊角色的攻击动画和武器锚点
- 在Wave数据中添加熊角色作为Boss
- 新增熊角色的子弹资源SunDance

scripts/Contents/Characters/Bear.gd

@@ -1,8 +1,17 @@
 extends EntityBase
 class_name Bear # 攻击方式模仿泰拉瑞亚光之女皇
 
+func register():
+	fields[FieldStore.Entity.MAX_HEALTH] = 2000
+	fields[FieldStore.Entity.MOVEMENT_SPEED] = 0.25
+	attackCooldownMap[0] = 100
+func spawn():
+	texture.play("walk")
 func ai():
-	pass
+	PresetEntityAI.follow(self, currentFocusedBoss, 0)
+	tryAttack(0)
 func attack(type):
+	var weaponPos = findWeaponAnchor("normal")
 	if type == 0:
-		pass
+		for bullet in BulletBase.generate(preload("res://components/Bullets/BossAttack/Bear/ArrowSeven.tscn"), self, weaponPos, deg_to_rad(randf_range(0, 360))):
+			bullet.tracer = currentFocusedBoss