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/game-object/get-components-in-children.md

@@ -0,0 +1,20 @@
+# GameObject::GetComponentsInChildren
+
+获取所有子对象中指定类型的组件。
+
+```cpp
+template<typename T>
+std::vector<T*> GetComponentsInChildren();
+```
+
+递归搜索所有子对象，返回所有匹配类型的组件。
+
+**模板参数：**
+- `T` - 组件类型
+
+**返回：** `std::vector<T*>` - 包含所有匹配组件的向量
+
+## 相关文档
+
+- [GameObject 总览](game-object.md)
+- [GetComponentInChildren](get-component-in-children.md)