docs: update resources API docs

docs/api/resources/shader/getguid.md

@@ -0,0 +1,25 @@
+# Shader::GetGUID
+
+```cpp
+ResourceGUID GetGUID() const override
+```
+
+获取着色器资源的全局唯一标识符。
+
+**返回：** `ResourceGUID` - 全局唯一标识符
+
+**线程安全：** ✅ 线程安全
+
+**复杂度：** O(1)
+
+**示例：**
+
+```cpp
+ResourceHandle<Shader> shader = ResourceManager::Get().Load<Shader>("shaders/vertex.glsl");
+ResourceGUID guid = shader->GetGUID();
+```
+
+## 相关文档
+
+- [Shader 总览](shader.md) - 返回类总览
+- [IResource](../iresource/iresource.md) - 资源基类