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/ExperimentConfig.cs

@@ -0,0 +1,38 @@
+using UnityEngine;
+
+/// <summary>
+/// 单个实验类型的完整配置：包含学习模式与考核模式的所有步骤。
+/// 在 Unity Editor 中为每种实验类型各创建一份 Asset。
+/// </summary>
+[CreateAssetMenu(fileName = "ExperimentConfig", menuName = "VFS/Experiment Config")]
+public class ExperimentConfig : ScriptableObject
+{
+    [Header("实验标识")]
+    public ExperimentType Type;
+    [Header("实验名称")]
+    public string DisplayName;
+    [Header("骨折固定专属 - 固定方式对应的步骤覆盖")]
+    public FixationMethod DefaultFixationMethod = FixationMethod.LimbFixation;
+    [Header("学习模式步骤列表（肢体固定）")]
+    public StepData[] LearnStepsLimb;
+    [Header("学习模式步骤列表（夹板固定）")]
+    public StepData[] LearnStepsSplint;
+    [Header("考核模式步骤列表（肢体固定）")]
+    public StepData[] ExamStepsLimb;
+    [Header("考核模式步骤列表（夹板固定）")]
+    public StepData[] ExamStepsSplint;
+
+    public StepData[] GetStepsFor(ExperimentMode mode, FixationMethod fixation)
+    {
+        if (mode == ExperimentMode.Learn)
+            return fixation == FixationMethod.SplintFixation ? LearnStepsSplint : LearnStepsLimb;
+        else
+            return fixation == FixationMethod.SplintFixation ? ExamStepsSplint : ExamStepsLimb;
+    }
+
+    public int StepCount(ExperimentMode mode, FixationMethod fixation)
+    {
+        var steps = GetStepsFor(mode, fixation);
+        return steps != null ? steps.Length : 0;
+    }
+}