fix: improve doc link navigation and tree display

- Fix link resolution with proper relative/absolute path handling
- Improve link styling with underline decoration
- Hide leaf nodes from tree, only show directories
- Fix log file path for packaged app

docs/api/math/aabb/getaxis.md

@@ -0,0 +1,23 @@
+# OBB::GetAxis
+
+```cpp
+Vector3 GetAxis(int index) const
+```
+
+获取 OBB 的局部坐标轴。
+
+**参数：**
+- `index` - 轴索引（0=X轴, 1=Y轴, 2=Z轴）
+
+**返回：** `Vector3` - 对应轴的方向向量
+
+**复杂度：** O(1)
+
+**示例：**
+
+```cpp
+OBB obb = ...;
+Vector3 xAxis = obb.GetAxis(0);  // 局部 X 轴
+Vector3 yAxis = obb.GetAxis(1);  // 局部 Y 轴
+Vector3 zAxis = obb.GetAxis(2);  // 局部 Z 轴
+```