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

@@ -0,0 +1,19 @@
+# RHISwapChain::GetCurrentBackBufferIndex
+
+```cpp
+virtual uint32_t GetCurrentBackBufferIndex() const = 0;
+```
+
+获取当前后台缓冲区索引。
+
+**返回：** 当前后台缓冲区索引
+
+**示例：**
+
+```cpp
+uint32_t index = swapChain->GetCurrentBackBufferIndex();
+```
+
+## 相关文档
+
+- [RHISwapChain 总览](swap-chain.md) - 返回类总览