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/threading/task-group/setcompletecallback.md

@@ -0,0 +1,36 @@
+# TaskGroup::SetCompleteCallback
+
+```cpp
+void SetCompleteCallback(Callback&& callback)
+```
+
+设置任务组完成回调。当所有任务都完成后，回调函数将在某个工作线程中被调用。
+
+**参数：**
+- `callback` - 完成时要调用的回调函数
+
+**返回：** 无
+
+**复杂度：** O(1)
+
+**示例：**
+
+```cpp
+TaskGroup* group = TaskSystem::Get().CreateTaskGroup();
+
+group->AddTask([]() { LoadTextures(); });
+group->AddTask([]() { LoadMeshes(); });
+group->AddTask([]() { LoadAudio(); });
+
+group->SetCompleteCallback([]() {
+    printf("All assets loaded!\n");
+    ResourceManager::InitGPUResources();
+});
+
+group->Wait();
+TaskSystem::Get().DestroyTaskGroup(group);
+```
+
+## 相关文档
+
+- [TaskGroup 总览](task-group.md) - 返回类总览