docs: update math API docs

docs/api/math/quaternion/to-matrix4x4.md

@@ -0,0 +1,30 @@
+# Quaternion::ToMatrix4x4
+
+```cpp
+Matrix4x4 ToMatrix4x4() const;
+```
+
+将四元数转换为 4x4 旋转矩阵。
+
+**返回：** 4x4 旋转矩阵
+
+**线程安全：** ✅
+
+**复杂度：** O(1)
+
+**示例：**
+
+```cpp
+#include <XCEngine/Math/Quaternion.h>
+#include <XCEngine/Math/Matrix4.h>
+
+using namespace XCEngine::Math;
+
+Quaternion q = Quaternion::FromAxisAngle(Vector3::Up(), Math::Radians(90.0f));
+Matrix4 m = q.ToMatrix4x4();
+```
+
+## 相关文档
+
+- [Quaternion](quaternion.md) - 返回类总览
+- [FromRotationMatrix](from-rotation-matrix.md) - 从矩阵创建