Fix chat rendering and improve scroll behavior

- Emit SegmentsRole in dataChanged signals so QML updates properly
- Add onContentHeightChanged to scroll when content loads after session switch
- Add floating scroll-to-bottom button that appears when scrolled up
- Wrap chat ScrollView in Item to allow button overlay

gui/chatblockmodel.cpp

@@ -223,7 +223,7 @@ void ChatBlockModel::appendData(const QString &text)
         
         // But emit with the rendered HTML that includes partial content
         QModelIndex idx = index(m_blocks.size() - 1);
-        emit dataChanged(idx, idx, {RenderedHtmlRole});
+        emit dataChanged(idx, idx, {RenderedHtmlRole, SegmentsRole});
     }
 }
 
@@ -483,7 +483,7 @@ void ChatBlockModel::appendContent(const QString &line)
     rebuildBlockHtml(m_blocks.size() - 1);
 
     QModelIndex idx = index(m_blocks.size() - 1);
-    emit dataChanged(idx, idx, {ContentRole, RenderedHtmlRole});
+    emit dataChanged(idx, idx, {ContentRole, RenderedHtmlRole, SegmentsRole});
 }
 
 void ChatBlockModel::processLine(const QString &line)

gui/main.qml

@@ -1220,64 +1220,74 @@ ApplicationWindow {
 
             Rectangle { Layout.fillWidth: true; height: 1; color: theme.midColor }
 
-            // Chat display — block-based ListView
+            // Chat display — block-based ListView with scroll-to-bottom button
-            ScrollView {
+            Item {
                 Layout.fillWidth: true
                 Layout.fillHeight: true
-                clip: true
                 
-                // Placeholder when no agent selected or disconnected
+                ScrollView {
-                Label {
-                    anchors.centerIn: parent
-                    text: {
-                        if (!ollie.daemonConnected) return "Not connected"
-                        if (!ollie.activeSessionId) return "Select a session"
-                        return "Select an agent to view chat"
-                    }
-                    color: theme.midColor
-                    font.italic: true
-                    font.pixelSize: theme.fontSize > 0 ? theme.fontSize : 12
-                    visible: !ollie.activeAgentId || !ollie.daemonConnected
-                }
-
-                ListView {
-                    id: chatView
-                    model: chatModel
-                    spacing: 4
                     anchors.fill: parent
-                    anchors.margins: 4
+                    clip: true
-                    boundsBehavior: Flickable.StopAtBounds
-                    visible: ollie.daemonConnected && ollie.activeAgentId !== ""
 
-                    // Auto-scroll when near bottom (within ~50px or at end)
+                    // Placeholder when no agent selected or disconnected
-                    // Reset to true on new blocks, user can scroll up to disable
+                    Label {
-                    property bool shouldAutoScroll: true
+                        anchors.centerIn: parent
-                    readonly property bool nearBottom: contentHeight - contentY - height < 50
+                        text: {
-
+                            if (!ollie.daemonConnected) return "Not connected"
-                    onContentYChanged: {
+                            if (!ollie.activeSessionId) return "Select a session"
-                        // User scrolled up - disable auto-scroll
+                            return "Select an agent to view chat"
-                        // User scrolled to bottom - re-enable
-                        if (dragging || flicking) {
-                            shouldAutoScroll = nearBottom || atYEnd
                         }
+                        color: theme.midColor
+                        font.italic: true
+                        font.pixelSize: theme.fontSize > 0 ? theme.fontSize : 12
+                        visible: !ollie.activeAgentId || !ollie.daemonConnected
                     }
 
-                    onCountChanged: {
+                    ListView {
-                        // New block added - always scroll if we were following
+                        id: chatView
-                        if (count > 0) {
+                        model: chatModel
-                            if (shouldAutoScroll)
+                        spacing: 4
-                                scrollTimer.start()
+                        anchors.fill: parent
-                        }
+                        anchors.margins: 4
-                    }
+                        boundsBehavior: Flickable.StopAtBounds
+                        visible: ollie.daemonConnected && ollie.activeAgentId !== ""
 
-                    Connections {
+                        // Auto-scroll when near bottom (within ~50px or at end)
-                        target: chatModel
+                        // Reset to true on new blocks, user can scroll up to disable
-                        function onDataChanged() {
+                        property bool shouldAutoScroll: true
-                            // Content updated (streaming) - scroll if following
+                        readonly property bool nearBottom: contentHeight - contentY - height < 50
-                            if (chatView.shouldAutoScroll && chatView.count > 0)
+
-                                scrollTimer.start()
+                        onContentYChanged: {
+                            // User scrolled up - disable auto-scroll
+                            // User scrolled to bottom - re-enable
+                            if (dragging || flicking) {
+                                shouldAutoScroll = nearBottom || atYEnd
+                            }
+                        }
+                        
+                        onContentHeightChanged: {
+                            // Content height changed (e.g., after loading) - scroll if following
+                            if (shouldAutoScroll && count > 0) {
+                                positionViewAtEnd()
+                            }
+                        }
+
+                        onCountChanged: {
+                            // New block added - always scroll if we were following
+                            if (count > 0) {
+                                if (shouldAutoScroll)
+                                    scrollTimer.start()
+                            }
+                        }
+
+                        Connections {
+                            target: chatModel
+                            function onDataChanged() {
+                                // Content updated (streaming) - scroll if following
+                                if (chatView.shouldAutoScroll && chatView.count > 0)
+                                    scrollTimer.start()
+                            }
                         }
-                    }
 
 delegate: ColumnLayout {
                         id: blockItem
@@ -1585,6 +1595,38 @@ property bool blockExpanded: {
         }
                     }
                 }
+                }
+                
+                // Scroll-to-bottom floating button
+                Rectangle {
+                    id: scrollToBottomBtn
+                    width: 40
+                    height: 40
+                    radius: 20
+                    color: theme.highlightColor
+                    opacity: 0.9
+                    anchors.right: parent.right
+                    anchors.bottom: parent.bottom
+                    anchors.margins: 16
+                    visible: !chatView.shouldAutoScroll && chatView.count > 0 && chatView.visible
+                    
+                    Label {
+                        anchors.centerIn: parent
+                        text: "↓"
+                        font.pixelSize: 20
+                        font.bold: true
+                        color: theme.highlightedTextColor
+                    }
+                    
+                    MouseArea {
+                        anchors.fill: parent
+                        cursorShape: Qt.PointingHandCursor
+                        onClicked: {
+                            chatView.shouldAutoScroll = true
+                            chatView.positionViewAtEnd()
+                        }
+                    }
+                }
             }
 
             Rectangle { Layout.fillWidth: true; height: 1; color: theme.midColor }