revert: restore BeginCapture/EndCapture instead of TriggerCapture

TriggerCapture caused incomplete rdc files due to async file writing.
BeginCapture/EndCapture ensures synchronous file write on EndCapture.

tests/RHI/D3D12/integration/minimal/main.cpp

@@ -279,11 +279,34 @@ int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine
             ExecuteCommandList();
 
             if (frameCount >= targetFrameCount) {
-                RenderDocCapture::Get().TriggerCapture();
-                Log("[INFO] RenderDoc capture triggered");
+                if (RenderDocCapture::Get().EndCapture()) {
+                    Log("[INFO] RenderDoc capture ended");
+                }
+                WaitForGPU();
+                Log("[INFO] GPU idle, taking screenshot...");
+                bool screenshotResult = D3D12Screenshot::Capture(
+                    gDevice,
+                    gCommandQueue,
+                    gSwapChain.GetBackBuffer(gCurrentRTIndex),
+                    "minimal.ppm"
+                );
+                if (screenshotResult) {
+                    Log("[INFO] Screenshot saved to minimal.ppm");
+                } else {
+                    Log("[ERROR] Screenshot failed");
+                }
+                Log("[INFO] RenderDoc capture completed");
+                break;
             }
 
-            // Present
+            if (frameCount == targetFrameCount - 1) {
+                if (RenderDocCapture::Get().BeginCapture("D3D12_Minimal_Test")) {
+                    Log("[INFO] RenderDoc capture started");
+                }
+            }
+
+            EndRender();
+            ExecuteCommandList();
             gSwapChain.Present(0, 0);
 
             if (frameCount >= targetFrameCount) {