fix: keep streamed reasoning expanded

src/renderer/src/App.test.tsx

@@ -1399,6 +1399,11 @@ describe('App', () => {
         (_, element) => element?.textContent === rawToolOutput
       )
     ).toBeVisible()
+    const activeReasoning = screen.getAllByText('正在推理')
+    expect(activeReasoning).toHaveLength(2)
+    for (const reasoning of activeReasoning) {
+      expect(reasoning.closest('details')).toHaveAttribute('open')
+    }
 
     act(() => {
       if (!request) {

src/renderer/src/App.tsx

@@ -5446,11 +5446,7 @@ function App(): React.JSX.Element {
                           <details
                             className="message-reasoning"
                             key={item.block.id}
-                            open={
-                              message.state === 'streaming' &&
-                              message.blocks?.at(-1)?.id ===
-                                item.block.id
-                            }
+                            open={message.state === 'streaming'}
                           >
                             <summary>
                               {message.state === 'streaming'