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/resourcemanager/registerloader.md

@@ -0,0 +1,26 @@
+# ResourceManager::RegisterLoader
+
+```cpp
+void RegisterLoader(IResourceLoader* loader)
+```
+
+注册资源加载器。管理器持有加载器指针所有权。
+
+**参数：**
+- `loader` - 加载器实例指针
+
+**返回：** 无
+
+**复杂度：** O(1)
+
+**示例：**
+
+```cpp
+ResourceManager::Get().RegisterLoader(new TextureLoader());
+ResourceManager::Get().RegisterLoader(new MeshLoader());
+ResourceManager::Get().RegisterLoader(new MaterialLoader());
+```
+
+## 相关文档
+
+- [ResourceManager 总览](resourcemanager.md) - 返回类总览