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/rhi/d3d12/descriptor-heap/get-descriptor-heap.md

@@ -0,0 +1,15 @@
+# D3D12DescriptorHeap::GetDescriptorHeap
+
+```cpp
+ID3D12DescriptorHeap* GetDescriptorHeap() const { return m_descriptorHeap.Get(); }
+```
+
+获取底层 D3D12 描述符堆接口。
+
+**返回：** `ID3D12DescriptorHeap*`
+
+**复杂度：** O(1)
+
+## 相关文档
+
+- [D3D12DescriptorHeap 总览](descriptor-heap.md) - 返回类总览