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/exists.md

@@ -0,0 +1,28 @@
+# ResourceManager::Exists
+
+```cpp
+bool Exists(const Containers::String& path) const
+bool Exists(ResourceGUID guid) const
+```
+
+检查资源是否已加载。
+
+**参数：**
+- `path` - 资源路径
+- `guid` - 资源全局唯一标识符
+
+**返回：** 如果资源在缓存中则返回 true
+
+**复杂度：** O(1)
+
+**示例：**
+
+```cpp
+if (ResourceManager::Get().Exists("textures/player.png")) {
+    auto tex = ResourceManager::Get().Load<Texture>("textures/player.png");
+}
+```
+
+## 相关文档
+
+- [ResourceManager 总览](resourcemanager.md) - 返回类总览