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/shader/set-vec4.md

@@ -0,0 +1,17 @@
+# RHIShader::SetVec4
+
+```cpp
+virtual void SetVec4(const char* name, float x, float y, float z, float w) = 0;
+```
+
+设置四维向量 uniform。
+
+**参数：**
+- `name` - uniform 变量名
+- `x, y, z, w` - 向量分量
+
+**复杂度：** O(1)
+
+## 相关文档
+
+- [RHIShader 总览](shader.md) - 返回类总览