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/matrix3/identity.md

@@ -0,0 +1,17 @@
+# Matrix3::Identity
+
+```cpp
+static Matrix3 Identity()
+```
+
+返回 3x3 单位矩阵。
+
+**返回：** `Matrix3` - 单位矩阵
+
+**复杂度：** O(1)
+
+**示例：**
+
+```cpp
+Matrix3 identity = Matrix3::Identity();
+```