fix: Copy button can flow in expanded codeblock

ChatView/qml/RootItem.qml

@@ -272,6 +272,7 @@ ChatRootView {
                     id: chatItemInstance
 
                     width: parent.width
+                    chatViewport: chatListView
                     msgModel: root.chatModel.processMessageContent(model.content)
                     messageAttachments: model.attachments
                     messageImages: model.images

ChatView/qml/chatparts/ChatItem.qml

@@ -30,6 +30,7 @@ Rectangle {
     property int textFontSize: Qt.application.font.pointSize
     property int codeFontSize: Qt.application.font.pointSize
     property int textFormat: 0
+    property Flickable chatViewport: null
 
     property bool isUserMessage: false
     property int messageIndex: -1
@@ -259,6 +260,7 @@ Rectangle {
         language: itemData.language
         codeFontFamily: root.codeFontFamily
         codeFontSize: root.codeFontSize
+        viewport: root.chatViewport
     }
 
     component AttachmentComponent : Rectangle {

ChatView/qml/chatparts/CodeBlock.qml

@@ -13,6 +13,7 @@ Rectangle {
     property string code: ""
     property string language: ""
     property bool expanded: false
+    property Flickable viewport: null
 
     property alias codeFontFamily: codeText.font.family
     property alias codeFontSize: codeText.font.pointSize
@@ -122,7 +123,16 @@ Rectangle {
         anchors.right: parent.right
         anchors.rightMargin: 5
 
-        y: 5
+        y: {
+            if (!root.expanded || !root.viewport)
+                return 5
+            const flick = root.viewport
+            const topInContent = root.mapToItem(flick.contentItem, 0, 0).y
+            const topInView = topInContent - flick.contentY
+            const desired = topInView < 0 ? (-topInView + 5) : 5
+            const maxY = Math.max(5, root.height - copyButton.height - 5)
+            return Math.max(5, Math.min(desired, maxY))
+        }
         text: qsTr("Copy")
 
         onClicked: {