feat(engine): C++ native script system (ScriptBehavior + registry)

ScriptComponent stores only a script name string (POD, serializable);
instances are reconciled by ScriptRuntime each frame (PhysicsWorld
pattern): orphan/rename cleanup with OnDestroy, per-name instantiation
from a file-level self-registering registry (ENGINE_REGISTER_SCRIPT),
OnCreate on bind, OnUpdate after physics step on scaled dt. Engine
framerate loop only sees the base interface, so future Lua/C# behaviors
plug in as foreign ScriptBehavior implementations with zero engine
changes. Ships a Spinner sample script and Inspector script picker.

App/scripts/Spinner.cpp

@@ -0,0 +1,38 @@
+//
+// Spinner.cpp：C++ 原生脚本示范——Y 轴匀速自转。
+//
+// 写脚本三步：
+//   1. 新建 .cpp 放本目录（CMake 自动进构建）
+//   2. 继承 ScriptBehavior，覆写 Name/OnCreate/OnUpdate/OnDestroy
+//   3. 文件级 ENGINE_REGISTER_SCRIPT(类名) 自注册——Inspector 下拉
+//      与场景序列化按该名解析
+//
+
+#include <Engine/Scripting/Script.h>
+
+#include <glm/gtc/quaternion.hpp>
+
+namespace {
+
+    class Spinner final : public Engine::Scripting::ScriptBehavior {
+    public:
+        const char* Name() const override { return "Spinner"; }
+
+        void OnCreate() override {
+            // 实体与组件已就位；需要别的组件时用 Get<T>()（不存在会炸）
+        }
+
+        void OnUpdate(float dt) override {
+            // 四元数复合绕 Y（避免每帧欧拉↔四元数往返累积失真）
+            const glm::quat step = glm::angleAxis(
+                glm::radians(m_Speed * dt), glm::vec3(0.0f, 1.0f, 0.0f));
+            Transform().SetRotationQuat(step * Transform().GetRotationQuat());
+        }
+
+    private:
+        float m_Speed = 90.0f; // 度/秒
+    };
+
+    ENGINE_REGISTER_SCRIPT(Spinner)
+
+} // namespace