fix(acp): scroll to the first question when a form appears

A new ask_user form scrolled the transcript to the bottom, so long
forms opened on their last question. The view now scrolls the form's
top into view and stops following the stream until the next send, so
text the agent writes after the form does not push it away.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: nullmastermind

src/widgets/AcpSessionView.cpp

@@ -95,6 +95,10 @@ bool askUserCallDropped(const QString &status)
 // bottom". Used both for the user's at-bottom recognition (the flag flips on
 // when they reach this band) and for the programmatic scroll target.
 constexpr int kAtBottomEpsilonPx = 8;
+// Space kept above a form scrolled into view, and a second pass once the
+// form's own layout has settled.
+constexpr int kFormScrollMarginPx = 8;
+constexpr int kFormScrollSettleMs = 60;
 constexpr int kMaxSkillCompletions = 256;
 
 bool isEffortConfigOption(const AcpProtocol::AcpConfigOption &opt)
@@ -2206,9 +2210,9 @@ void AcpSessionView::presentForm(const AskUserForm::Spec &spec, FormSource sourc
     auto *form = new AskUserFormWidget(spec, initial, m_transcriptHost);
     form->setChatFont(chatFont());
     insertTimelineWidget(form);
-    scrollToBottomDeferred();
 
     if (isUnattended()) {
+        scrollToBottomDeferred();
         const bool goal = m_goalRunning;
         form->setState(AskUserFormWidget::State::Cancelled,
                        goal ? tr("Cancelled — goal agent active") : tr("Cancelled — unattended session"));
@@ -2234,6 +2238,32 @@ void AcpSessionView::presentForm(const AskUserForm::Spec &spec, FormSource sourc
     // Take focus only from an empty composer the user is sitting in.
     if (m_input && m_input->hasFocus() && m_input->toPlainText().trimmed().isEmpty())
         form->focusFirstQuestion();
+    scrollToFormTop(form);
+}
+
+void AcpSessionView::scrollToFormTop(QWidget *form)
+{
+    // Show question 1, not the bottom: stop following the stream (text the
+    // agent writes after the form would push it away) until the next send.
+    m_stickToBottom = false;
+    updateJumpButtonVisibility();
+    QPointer<AcpSessionView> guard(this);
+    QPointer<QWidget> target(form);
+    auto apply = [guard, target]() {
+        if (!guard || !target || !guard->m_scroll || !guard->m_transcriptHost)
+            return;
+        auto *vb = guard->m_scroll->verticalScrollBar();
+        if (!vb)
+            return;
+        const int top = target->mapTo(guard->m_transcriptHost, QPoint(0, 0)).y() - kFormScrollMarginPx;
+        guard->m_programmaticScroll = true;
+        vb->setValue(qBound(vb->minimum(), top, vb->maximum()));
+        guard->m_programmaticScroll = false;
+        guard->updateJumpButtonVisibility();
+    };
+    // Once after the insert is laid out, once more after the form has sized.
+    QTimer::singleShot(0, this, apply);
+    QTimer::singleShot(kFormScrollSettleMs, this, apply);
 }
 
 void AcpSessionView::settlePendingForm(AskUserFormWidget::State state, const QString &detail,

src/widgets/AcpSessionView.h

@@ -267,6 +267,8 @@ private slots:
                         bool fromGoalAgent = false);
     bool isUnattended() const;
     void restoreExpiredForm();
+    // Scroll so the form's first question is at the top; stops following the stream.
+    void scrollToFormTop(QWidget *form);
     void applyMessageMarker(AcpMessageWidget *w, int messageIndex);
     bool inputKeyEventIsSubmit(QKeyEvent *ke) const;
     // Heartbeat indicator at the tail of the transcript: shows time since the