refactor(UI): 调整技能图标布局并优化冷却效果

修改技能图标面板的锚点设置以改善布局
将冷却进度着色器逻辑反转并优化视觉效果
统一材质管理方式，移除重复的材质复制

scripts/Statemachine/SkillIcon.gd

@@ -4,11 +4,10 @@ class_name SkillIcon
 @export var weapon: Weapon = null;
 
 @onready var textureRect: TextureRect = $"%texture"
-
 func _ready():
-	textureRect.material = textureRect.material.duplicate()
+	material = material.duplicate()
 func _physics_process(_delta):
 	if is_instance_valid(weapon):
 		textureRect.texture = weapon.avatarTexture
 		var progress = min(weapon.cooldownTimer.timeSinceLastStart() / weapon.cooldownTimer.cooldown, UIState.player.energy / weapon.needEnergy)
-		textureRect.material.set_shader_parameter("progress", progress)
+		material.set_shader_parameter("progress", progress)