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/rectint-getsize.md

@@ -0,0 +1,18 @@
+# RectInt::GetSize
+
+```cpp
+Vector2 GetSize() const
+```
+
+获取矩形尺寸（转换为浮点）。
+
+**返回：** `Vector2` - 尺寸向量
+
+**复杂度：** O(1)
+
+**示例：**
+
+```cpp
+RectInt rect(10, 20, 100, 50);
+Vector2 size = rect.GetSize();  // (100.0f, 50.0f)
+```