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-current-back-buffer-index.md

@@ -0,0 +1,30 @@
+# D3D12SwapChain::GetCurrentBackBufferIndex
+
+## 函数签名
+
+```cpp
+uint32_t GetCurrentBackBufferIndex() const override
+```
+
+## 中文描述
+
+获取当前后台缓冲区的索引。
+
+## 返回值
+
+`uint32_t` - 当前后台缓冲区索引
+
+## 复杂度
+
+O(1)
+
+## 示例
+
+```cpp
+uint32_t index = swapChain->GetCurrentBackBufferIndex();
+```
+
+## 相关文档
+
+- [D3D12SwapChain](swap-chain.md) - 类总览
+- [D3D12SwapChain::GetCurrentBackBuffer](get-current-back-buffer.md) - 获取当前后台缓冲区