feat(UI): 添加物品收集显示功能

- 新增CameraManager脚本用于相机管理
- 在UI场景中添加物品收集容器VBoxContainer
- 扩展ItemShow类支持生成物品显示实例
- 修改EntityBase添加物品收集信号和处理逻辑
- 调整BossBar位置和布局属性

components/Scenes/World.tscn

@@ -1,8 +1,9 @@
-[gd_scene load_steps=5 format=3 uid="uid://dmxi1ikn6avig"]
+[gd_scene load_steps=6 format=3 uid="uid://dmxi1ikn6avig"]
 
 [ext_resource type="Script" path="res://scripts/Tools/WorldManager.gd" id="1_lxsxj"]
 [ext_resource type="PackedScene" uid="uid://dfwg750a47ggx" path="res://components/Scenes/UI.tscn" id="2_04cdd"]
 [ext_resource type="PackedScene" uid="uid://bm7ymrri6pykb" path="res://components/Characters/Rooster.tscn" id="3_5ui6q"]
+[ext_resource type="Script" path="res://scripts/Tools/CameraManager.gd" id="5_mk7bv"]
 [ext_resource type="Texture2D" uid="uid://ckk8kahhof06u" path="res://resources/maps/Castle 2.png" id="6_p0nkj"]
 
 [node name="world" type="Node2D"]
@@ -24,3 +25,4 @@ process_mode = 3
 position = Vector2(0, -100)
 process_callback = 0
 position_smoothing_enabled = true
+script = ExtResource("5_mk7bv")