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/swap-chain/get-back-buffer.md

@@ -0,0 +1,35 @@
+# D3D12SwapChain::GetBackBuffer
+
+## 函数签名
+
+```cpp
+D3D12Texture* GetBackBuffer(uint32_t index) const
+```
+
+## 中文描述
+
+获取指定索引的后台缓冲区。
+
+## 参数
+
+| 参数 | 类型 | 描述 |
+|------|------|------|
+| `index` | `uint32_t` | 缓冲区索引 |
+
+## 返回值
+
+`D3D12Texture*` - 后台缓冲区纹理指针
+
+## 复杂度
+
+O(1)
+
+## 示例
+
+```cpp
+D3D12Texture* buffer = swapChain->GetBackBuffer(0);
+```
+
+## 相关文档
+
+- [D3D12SwapChain](swap-chain.md) - 类总览