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/rect/viewport-getaspectratio.md

@@ -0,0 +1,18 @@
+# Viewport::GetAspectRatio
+
+```cpp
+float GetAspectRatio() const
+```
+
+获取视口宽高比。
+
+**返回：** `float` - 宽高比 (width / height)，height 为 0 时返回 0.0f
+
+**复杂度：** O(1)
+
+**示例：**
+
+```cpp
+Viewport viewport(0, 0, 1920, 1080);
+float aspect = viewport.GetAspectRatio();  // 1.777... (16:9)
+```