내부 설정 스크롤 체감과 저장 공간 버튼 스타일 개선

AX Agent 내부 설정 오른쪽 본문 ScrollViewer에 deferred scrolling, vertical panning, bitmap cache를 적용해 스크롤 시 버벅임을 줄였습니다.

저장 공간 섹션의 새로고침, 대화 삭제, 저장 공간 줄이기 버튼을 OverlayActionBtn 커스텀 스타일로 교체해 일반 버튼 느낌을 제거했습니다.

README와 DEVELOPMENT 문서를 2026-04-06 16:39 (KST) 기준으로 갱신했고 Release 빌드 경고 0 오류 0을 확인했습니다.

README.md

@@ -1276,3 +1276,6 @@ MIT License
 - 업데이트: 2026-04-06 16:28 (KST)
   - 채팅/코워크/코드 입력창의 첨부/전송 버튼을 다시 심플한 컴포저 전용 스타일로 정리했다. [ChatWindow.xaml](/E:/AX%20Copilot%20-%20Codex/src/AxCopilot/Views/ChatWindow.xaml)에 `ComposerIconBtn`, `ComposerSendBtn` 스타일을 추가해 버튼 크기를 원복 수준으로 줄이고, 첨부와 전송 모두 상하좌우 중앙 정렬된 단순한 시각 언어를 사용하도록 맞췄다.
   - 첨부 버튼은 과하게 커졌던 `48x48`에서 `34x34` 기준으로 줄였고, 전송 버튼도 같은 축의 `36x36` 원형 버튼으로 재구성했다. 전송 아이콘은 과한 MDL2 느낌 대신 단순한 상승 화살표 표현으로 바꿔, 참고 이미지처럼 더 담백한 조합이 되도록 정리했다.
+- 업데이트: 2026-04-06 16:39 (KST)
+  - AX Agent 내부 설정 오른쪽 본문 [ChatWindow.xaml](/E:/AX%20Copilot%20-%20Codex/src/AxCopilot/Views/ChatWindow.xaml)의 `ScrollViewer`에 `IsDeferredScrollingEnabled`, `PanningMode`, `BitmapCache`를 적용해 스크롤 시 느껴지던 버벅임을 줄였다.
+  - `저장 공간` 섹션의 `새로고침`, `대화 삭제`, `저장 공간 줄이기`는 기본 `Button` 대신 오버레이 전용 커스텀 액션 버튼 스타일(`OverlayActionBtn`)로 교체해 내부 설정 전체와 같은 시각 언어를 사용하도록 정리했다.

docs/DEVELOPMENT.md

@@ -4975,3 +4975,5 @@ ow + toggle ?쒓컖 ?몄뼱濡??ㅼ떆 ?뺣젹?덈떎.
 - Document update: 2026-04-06 16:20 (KST) - Re-ran the standard verification build after those fixes and restored the zero-warning requirement: `dotnet build src/AxCopilot/AxCopilot.csproj -c Release -v minimal -p:OutputPath=bin\verify\ -p:IntermediateOutputPath=obj\verify\` now completes with 0 warnings and 0 errors.
 - Document update: 2026-04-06 16:28 (KST) - Refined the chat/composer action buttons in `ChatWindow.xaml` by introducing dedicated `ComposerIconBtn` and `ComposerSendBtn` styles. The oversized attachment/send controls were reduced back toward their earlier footprint and given a simpler, more centered visual language.
 - Document update: 2026-04-06 16:28 (KST) - The attachment button now uses a compact `34x34` ghost surface and the send button uses a matching `36x36` circular emphasis surface with a centered upward arrow glyph, replacing the larger prior styling and making the footer composer closer to the requested minimal reference.
+- Document update: 2026-04-06 16:39 (KST) - Reduced the perceived lag while scrolling the AX Agent internal-settings overlay by enabling deferred scrolling and vertical panning on the right-side settings `ScrollViewer`, and by bitmap-caching the large stacked content block in `ChatWindow.xaml`.
+- Document update: 2026-04-06 16:39 (KST) - Replaced the plain storage-management buttons in the internal settings overlay with a new `OverlayActionBtn` style so `새로고침`, `대화 삭제`, and `저장 공간 줄이기` follow the same custom rounded action language as the rest of the AX Agent settings UI.

src/AxCopilot/Views/ChatWindow.xaml

@@ -161,6 +161,44 @@
             <Setter Property="Padding" Value="14,12"/>
             <Setter Property="Margin" Value="0,0,0,8"/>
         </Style>
+        <Style x:Key="OverlayActionBtn" TargetType="Button">
+            <Setter Property="Background" Value="{DynamicResource ItemBackground}"/>
+            <Setter Property="Foreground" Value="{DynamicResource PrimaryText}"/>
+            <Setter Property="BorderBrush" Value="{DynamicResource BorderColor}"/>
+            <Setter Property="BorderThickness" Value="1"/>
+            <Setter Property="Padding" Value="12,7"/>
+            <Setter Property="Margin" Value="0,0,8,0"/>
+            <Setter Property="Cursor" Value="Hand"/>
+            <Setter Property="FontSize" Value="12"/>
+            <Setter Property="Template">
+                <Setter.Value>
+                    <ControlTemplate TargetType="Button">
+                        <Border x:Name="ActionBorder"
+                                Background="{TemplateBinding Background}"
+                                BorderBrush="{TemplateBinding BorderBrush}"
+                                BorderThickness="{TemplateBinding BorderThickness}"
+                                CornerRadius="10"
+                                Padding="{TemplateBinding Padding}"
+                                SnapsToDevicePixels="True">
+                            <ContentPresenter HorizontalAlignment="Center"
+                                              VerticalAlignment="Center"
+                                              RecognizesAccessKey="True"/>
+                        </Border>
+                        <ControlTemplate.Triggers>
+                            <Trigger Property="IsMouseOver" Value="True">
+                                <Setter TargetName="ActionBorder" Property="Background" Value="{DynamicResource ItemHoverBackground}"/>
+                            </Trigger>
+                            <Trigger Property="IsPressed" Value="True">
+                                <Setter TargetName="ActionBorder" Property="Opacity" Value="0.82"/>
+                            </Trigger>
+                            <Trigger Property="IsEnabled" Value="False">
+                                <Setter TargetName="ActionBorder" Property="Opacity" Value="0.4"/>
+                            </Trigger>
+                        </ControlTemplate.Triggers>
+                    </ControlTemplate>
+                </Setter.Value>
+            </Setter>
+        </Style>
         <Style x:Key="OverlayHelpBadge" TargetType="Border">
             <Setter Property="Width" Value="16"/>
             <Setter Property="Height" Value="16"/>
@@ -2609,11 +2647,18 @@
                                                  Tag="block"/>
                                 </StackPanel>
                             </Border>
-                            <ScrollViewer Grid.Row="0" Grid.RowSpan="2" Grid.Column="1"
+                            <ScrollViewer x:Name="OverlaySettingsScrollViewer"
+                                          Grid.Row="0" Grid.RowSpan="2" Grid.Column="1"
                                           VerticalScrollBarVisibility="Auto"
                                           HorizontalScrollBarVisibility="Disabled"
+                                          CanContentScroll="False"
+                                          PanningMode="VerticalOnly"
+                                          IsDeferredScrollingEnabled="True"
                                           Padding="14,14,20,20">
                                 <StackPanel>
+                                    <StackPanel.CacheMode>
+                                        <BitmapCache RenderAtScale="1"/>
+                                    </StackPanel.CacheMode>
                                     <Border x:Name="OverlaySectionHeading"
                                             Background="Transparent"
                                             BorderBrush="{DynamicResource BorderColor}"
@@ -3426,17 +3471,16 @@
                                                                 VerticalAlignment="Top">
                                                         <Button x:Name="BtnOverlayStorageRefresh"
                                                                 Content="새로고침"
-                                                                Padding="10,6"
-                                                                Margin="0,0,8,0"
+                                                                Style="{StaticResource OverlayActionBtn}"
                                                                 Click="BtnOverlayStorageRefresh_Click"/>
                                                         <Button x:Name="BtnOverlayDeleteAllConversations"
                                                                 Content="대화 삭제"
-                                                                Padding="10,6"
-                                                                Margin="0,0,8,0"
+                                                                Style="{StaticResource OverlayActionBtn}"
                                                                 Click="BtnOverlayDeleteAllConversations_Click"/>
                                                         <Button x:Name="BtnOverlayStorageCleanup"
                                                                 Content="저장 공간 줄이기"
-                                                                Padding="12,6"
+                                                                Style="{StaticResource OverlayActionBtn}"
+                                                                Margin="0"
                                                                 Click="BtnOverlayStorageCleanup_Click"/>
                                                     </StackPanel>
                                                 </Grid>