docs: Add Component, GameObject, TransformComponent and Scene API documentation

- Add Component class documentation with lifecycle methods
- Add GameObject class documentation with component system
- Add TransformComponent documentation with transform methods
- Add Scene class documentation with GameObject management
- Add SceneManager singleton documentation with scene loading
- Update components.md overview with all component classes
- Update main.md navigation with Scene module

docs/api/components/component/get-game-object.md

@@ -0,0 +1,13 @@
+# Component::GetGameObject
+
+获取所属的 GameObject。
+
+```cpp
+GameObject* GetGameObject() const;
+```
+
+**返回：** `GameObject*` - 所属游戏对象指针，如果组件未附加到游戏对象则返回 nullptr
+
+## 相关文档
+
+- [Component 总览](component.md)