fix(seer): allow collapsing ThinkingBlock while thinking is active

static/app/components/core/chat/thinkingBlock.spec.tsx

@@ -55,6 +55,48 @@ describe('ThinkingBlock', () => {
     expect(screen.getByText('inner content')).not.toBeVisible();
   });
 
+  it('can be manually collapsed while thinking is active', async () => {
+    jest.useRealTimers();
+    const start = new Date();
+
+    render(
+      <ThinkingBlock title="Thinking" startTime={start}>
+        <div>inner content</div>
+      </ThinkingBlock>
+    );
+
+    expect(screen.getByText('inner content')).toBeVisible();
+
+    await userEvent.click(screen.getByText('Thinking'));
+    expect(screen.getByText('inner content')).not.toBeVisible();
+  });
+
+  it('auto-collapses when thinking completes even if user re-expanded', async () => {
+    jest.useRealTimers();
+    const start = new Date();
+
+    const {rerender} = render(
+      <ThinkingBlock title="Thinking" startTime={start}>
+        <div>inner content</div>
+      </ThinkingBlock>
+    );
+
+    // collapse then re-expand while still active
+    await userEvent.click(screen.getByText('Thinking'));
+    expect(screen.getByText('inner content')).not.toBeVisible();
+    await userEvent.click(screen.getByText('Thinking'));
+    expect(screen.getByText('inner content')).toBeVisible();
+
+    // thinking completes → auto-collapse
+    rerender(
+      <ThinkingBlock title="Thinking" startTime={start} endTime={new Date()}>
+        <div>inner content</div>
+      </ThinkingBlock>
+    );
+
+    expect(screen.getByText('inner content')).not.toBeVisible();
+  });
+
   it('can be manually toggled after collapsing', async () => {
     jest.useRealTimers();
     const start = new Date();

static/app/components/core/chat/thinkingBlock.tsx

@@ -74,20 +74,27 @@ interface ThinkingBlockProps {
 export function ThinkingBlock({title, startTime, endTime, children}: ThinkingBlockProps) {
   const elapsed = useElapsedTime(startTime, endTime);
   const isActive = !endTime;
-  const [userExpanded, setUserExpanded] = useState(false);
+  // ponytail: null = no user interaction, falls through to isActive default
+  const [override, setOverride] = useState<boolean | null>(null);
+
+  useEffect(() => {
+    if (!isActive) {
+      setOverride(null);
+    }
+  }, [isActive]);
 
   const titleRef = useRef<HTMLSpanElement>(null);
   // Strip trailing punctuation/whitespace so the animated ellipsis isn't
   // doubled up when the title already ends in "." or "…".
   const baseTitle = title.replace(/[.…\s]+$/u, '');
   useTextDecodeAnimation(titleRef, baseTitle);
 
-  const isExpanded = isActive || userExpanded;
+  const isExpanded = override ?? isActive;
 
   return (
     <Disclosure
       expanded={isExpanded}
-      onExpandedChange={setUserExpanded}
+      onExpandedChange={setOverride}
       size="sm"
       variant="outline"
       flex={1}