feat(UI): 为ColorBar添加currentValue属性并完善boss血条逻辑

为ColorBar组件添加currentValue属性以跟踪当前值。同时修复当设置boss时未正确更新血条显示的问题，确保boss血条在切换目标时能正确显示初始血量。

components/UI/ColorBar.tscn

@@ -36,6 +36,7 @@ anchors_preset = 0
 offset_right = 100.0
 offset_bottom = 10.0
 script = ExtResource("1_a106p")
+currentValue = 0.0
 backBox = SubResource("StyleBoxFlat_kf2fc")
 middleBox1 = SubResource("StyleBoxFlat_sh754")
 middleBox2 = SubResource("StyleBoxFlat_8n8i8")

scripts/Statemachine/BossBar.gd

@@ -4,9 +4,7 @@ class_name BossBar
 @onready var nameLabel: Label = $"%name"
 @onready var valueLabel: Label = $"%value"
 
-func _ready():
-	if is_instance_valid(entity):
-		nameLabel.text = entity.displayName
 func _process(_delta):
 	if is_instance_valid(entity):
+		nameLabel.text = entity.displayName
 		valueLabel.text = "%.2f" % (entity.health / entity.fields[FieldStore.Entity.MAX_HEALTH] * 100)

scripts/Statemachine/EntityBase.gd

@@ -202,8 +202,9 @@ func findWeaponAnchor(weaponName: String):
 		return Vector2.ZERO
 func setBoss(boss: EntityBase):
 	currentFocusedBoss = boss
-	if isPlayer():
+	if isPlayer() and boss and UIState.bossbar.entity != boss:
 		UIState.bossbar.entity = boss
+		boss.healthChanged.emit(boss.health)
 func playSound(type: String):
 	var body = sounds.get_node_or_null(type)
 	if body is AudioStreamPlayer2D: