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/resources/filesystem/exists.md

@@ -0,0 +1,26 @@
+# ResourceFileSystem::Exists
+
+```cpp
+bool Exists(const Containers::String& relativePath) const
+```
+
+检查资源文件是否存在。优先在归档包中查找，其次在目录中查找。
+
+**参数：**
+- `relativePath` - 资源相对路径
+
+**返回：** 如果存在则返回 true
+
+**复杂度：** O(1)
+
+**示例：**
+
+```cpp
+if (ResourceFileSystem::Get().Exists("shaders/default.vert")) {
+    // 文件存在...
+}
+```
+
+## 相关文档
+
+- [ResourceFileSystem 总览](filesystem.md) - 返回类总览