docs: update RHI API docs

docs/api/rhi/sampler/shutdown.md

@@ -4,10 +4,45 @@
 virtual void Shutdown() = 0;
 ```
 
-释放采样器资源。
+关闭并释放采样器资源。该方法用于在采样器不再需要时进行清理工作，释放底层图形 API 分配的资源。
+
+**参数：** 无
+
+**返回：** 无
+
+**线程安全：** ❌
 
 **复杂度：** O(1)
 
+**示例：**
+
+```cpp
+#include "XCEngine/RHI/RHISampler.h"
+
+class MySampler : public XCEngine::RHI::RHISampler {
+public:
+    void Shutdown() override {
+        if (m_initialized) {
+            ReleaseNativeResource();
+            m_initialized = false;
+        }
+    }
+    void Bind(unsigned int unit) override { }
+    void Unbind(unsigned int unit) override { }
+    void* GetNativeHandle() override { return nullptr; }
+    unsigned int GetID() override { return 0; }
+
+private:
+    bool m_initialized = true;
+    void ReleaseNativeResource() { }
+};
+
+void Example() {
+    MySampler sampler;
+    sampler.Shutdown();
+}
+```
+
 ## 相关文档
 
 - [RHISampler 总览](sampler.md) - 返回类总览