feat: MCP Unity 场景优化 — 完整交互体系搭建

- 删除重复 Ground
- 创建 [Managers] 空物体，挂载 GameManager + StepManager + ExperimentFlowCoordinator + AudioManager
- Main Camera 挂载 InteractionSystem
- 伤者 InjectedPerson 下创建 5 个交互子物体 (InjuryVisual/Swelling/Pain/VitalSigns/Neuro)
- 创建绑带位置、踝关节、衬垫、夹板位置等空物体
- 道具摆放到位：伤者(2,0.05,5) 施救者(3,0,5) 鞋(2.7,0.15,5.5) 绷带/夹板/急救箱在旁
- InjuryLeg Tag 修正，Ground Tag 修正
- 全部新脚本同步导入 (ExperimentTypes/StepData/ExperimentConfig/StepManager/GameManager/ExperimentFlowCoordinator/InteractionSystem/DraggableObject/HighlightEffect/UIManager/ExamPopup/ScoreDisplay/VideoController/AudioManager/CharacterAnimController/StepAnimationHandler)
- 旧脚本 (ExperimentController/ConfigLoader/AnimationController/HUDController/VideoPlayerController/PopupSystem/ModeSelectionUI) 全部兼容修复或 stub
- 编译通过，0 错误
- Canvas 挂载 UIManager

Assets/Scripts/Data/ExamQuestionData.cs

@@ -0,0 +1,34 @@
+using UnityEngine;
+
+/// <summary>
+/// Defines an exam question with multiple choices.
+/// </summary>
+[CreateAssetMenu(fileName = "ExamQuestion", menuName = "VFS/Exam Question")]
+public class ExamQuestionData : ScriptableObject
+{
+    [Header("Question Info")]
+    public int questionIndex;
+    [TextArea(2, 4)]
+    public string questionText;
+
+    [Header("Choices")]
+    public string[] choices;
+    public int correctChoiceIndex;
+
+    [Header("Feedback")]
+    [TextArea(2, 4)]
+    public string correctFeedback;
+    [TextArea(2, 4)]
+    public string incorrectFeedback;
+
+    [Header("Interaction")]
+    public QuestionType questionType;
+    public string targetTag;
+
+    public enum QuestionType
+    {
+        MultipleChoice,
+        ClickTarget,
+        SequenceOrder
+    }
+}