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/vector4/constructor-vector3.md

@@ -0,0 +1,25 @@
+# Vector4::Vector4 (from Vector3)
+
+```cpp
+explicit Vector4(const Vector3& v, float w = 0.0f)
+```
+
+从 Vector3 构造四维向量，w 分量默认为 0.0f。
+
+**参数：**
+- `v` - 源 Vector3 向量
+- `w` - W 分量（默认值为 `0.0f`）
+
+**返回：** 新创建的 Vector4 实例
+
+**示例：**
+
+```cpp
+Vector3 v3(1.0f, 2.0f, 3.0f);
+Vector4 v4a(v3);
+Vector4 v4b(v3, 1.0f);
+```
+
+## 相关文档
+
+- [Vector4 总览](vector4.md) - 返回类总览