docs: fix naming conventions across threading, math, memory, core, and debug modules

threading/:
- Rename 19 camelCase method files to hyphenated names
- task-system: createtaskgroup→create-task-group, etc.
- tasksystemconfig: enabletaskprofiling→enable-task-profiling, etc.
- thread: getcurrentid→get-current-id, etc.
- task: addref→add-ref, getid→get-id, etc.

math/:
- Rename underscore operator files to hyphenated
- vector3: operator_add→operator-add, etc.
- matrix4: gettranslation→get-translation, etc.
- vector4: tovector3→to-vector3, constructor_vector3→constructor-vector3
- sphere: sphere_constructor→sphere-constructor, etc.

memory/:
- Remove duplicate memorymanager/ folder (kept manager/ which was correct)

core/:
- filewriter: Consolidate ctor-default.md and ctor-file.md into constructor.md
- Rename dtor.md→destructor.md

debug/:
- filelogsink: Rename construct.md→constructor.md, ~filelogsink.md→destructor.md

All overview pages updated with new file references.

docs/api/math/matrix4/get-rotation.md

@@ -0,0 +1,42 @@
+# Matrix4x4::GetRotation
+
+```cpp
+Quaternion GetRotation() const
+```
+
+从变换矩阵中提取旋转分量。将矩阵转换为对应的四元数表示。
+
+**参数：** （无）
+
+**返回：** 旋转四元数
+
+**线程安全：** ✅
+
+**复杂度：** O(1)
+
+**示例：**
+
+```cpp
+#include "XCEngine/Math/Matrix4.h"
+#include "XCEngine/Math/Quaternion.h"
+
+using namespace XCEngine::Math;
+
+Quaternion expected = Quaternion::FromEuler(0.0f, 90.0f, 0.0f);
+Matrix4 transform = Matrix4::TRS(
+    Vector3(0.0f, 0.0f, 0.0f),
+    expected,
+    Vector3(1.0f, 1.0f, 1.0f)
+);
+
+Quaternion rotation = transform.GetRotation();
+// rotation 表示相同的旋转
+```
+
+## 相关文档
+
+- [Matrix4](matrix4.md) - 返回类总览
+- [Quaternion](../quaternion/quaternion.md) - 四元数类
+- [GetTranslation](gettranslation.md) - 获取平移分量
+- [GetScale](getscale.md) - 获取缩放分量
+- [Decompose](decompose.md) - 分解矩阵