refactor(P5b-6): 옵션/탭/충돌/결합 핸들러 5개 → 선언적 바인딩·커맨드 (의존성 0)

새 패키지 없이 회귀 없는 핸들러 제거/전환:
- OnQualityChanged 제거 → QualityValueText.Text를 Options.Quality에 StringFormat 바인딩.
- OnAiTaskChanged 제거 → AiTargetLangPanel.Visibility를 AiTaskCombo.SelectedIndex DataTrigger로.
- OnTabClick 제거 → TabCommand(ToggleButton.Command + CommandParameter "Active"/"Past").
- OnConflictSegmentClick → SetConflictRule + ConflictRuleCommand(CommandParameter "Skip/Rename/Replace").
- OnCombineToggleChanged 제거 → CombineToggleCommand(CheckBox.Command, 토글 시 발화).
- 검증: 빌드 0/0, 83 테스트 그린, publish 후 메인 창 크래시 없이 로드(언핸들드 로그 없음).
- 잔여: 동적 포맷 콤보 SelectionChanged, 드래그앤드롭, 행 미리보기 클릭(IsInsideButton 가드), 복합 ProcessQueue 버튼.

src/Everything2Everything.App/Views/MainWindow.xaml

@@ -107,8 +107,7 @@
                                           Margin="0,12,0,0"
                                           Content="단일 파일로 결합 (큐 전체 → 한 파일)"
                                           IsEnabled="False"
-                                          Checked="OnCombineToggleChanged"
+                                          Command="{Binding CombineToggleCommand, RelativeSource={RelativeSource AncestorType=Window}}"/>
-                                          Unchecked="OnCombineToggleChanged"/>
                                 <TextBlock x:Name="CombineHint" Margin="0,4,0,0"
                                            Style="{StaticResource FsCaptionStyle}"
                                            Text="PDF/TIFF/GIF 출력에 한해 큐의 이미지들을 한 파일로 결합합니다"/>
@@ -129,14 +128,13 @@
                                         <TextBlock x:Name="QualityValueText"
                                                    FontFamily="{StaticResource FsFontMono}" FontSize="12"
                                                    Foreground="{StaticResource FsAccentBlue}"
-                                                   Text="85%"/>
+                                                   Text="{Binding Options.Quality, RelativeSource={RelativeSource AncestorType=Window}, StringFormat={}{0}%}"/>
                                     </Border>
                                 </Grid>
                                 <Slider x:Name="QualitySlider" Margin="0,12,0,0"
                                         Style="{StaticResource FsSliderStyle}"
                                         Minimum="1" Maximum="100"
-                                        Value="{Binding Options.Quality, RelativeSource={RelativeSource AncestorType=Window}, Mode=TwoWay}"
+                                        Value="{Binding Options.Quality, RelativeSource={RelativeSource AncestorType=Window}, Mode=TwoWay}"/>
-                                        ValueChanged="OnQualityChanged"/>
                                 <Grid Margin="0,4,0,0">
                                     <Grid.ColumnDefinitions>
                                         <ColumnDefinition Width="*"/>
@@ -178,17 +176,17 @@
                                     <UniformGrid Rows="1" Columns="3">
                                         <ToggleButton x:Name="ConflictSkipBtn" Content="Skip"
                                                       Style="{StaticResource FsSegmentStyle}"
-                                                      Click="OnConflictSegmentClick"
+                                                      Command="{Binding ConflictRuleCommand, RelativeSource={RelativeSource AncestorType=Window}}"
-                                                      Tag="Skip"/>
+                                                      CommandParameter="Skip"/>
                                         <ToggleButton x:Name="ConflictRenameBtn" Content="Rename"
                                                       Style="{StaticResource FsSegmentStyle}"
                                                       IsChecked="True"
-                                                      Click="OnConflictSegmentClick"
+                                                      Command="{Binding ConflictRuleCommand, RelativeSource={RelativeSource AncestorType=Window}}"
-                                                      Tag="Rename"/>
+                                                      CommandParameter="Rename"/>
                                         <ToggleButton x:Name="ConflictReplaceBtn" Content="Replace"
                                                       Style="{StaticResource FsSegmentStyle}"
-                                                      Click="OnConflictSegmentClick"
+                                                      Command="{Binding ConflictRuleCommand, RelativeSource={RelativeSource AncestorType=Window}}"
-                                                      Tag="Replace"/>
+                                                      CommandParameter="Replace"/>
                                     </UniformGrid>
                                 </Border>
                             </StackPanel>
@@ -202,8 +200,7 @@
                                     <TextBlock Text="AI 작업" Style="{StaticResource FsLabelStyle}" VerticalAlignment="Center"/>
                                 </StackPanel>
                                 <ComboBox x:Name="AiTaskCombo" Margin="0,8,0,0"
-                                          SelectedIndex="0"
+                                          SelectedIndex="0">
-                                          SelectionChanged="OnAiTaskChanged">
                                     <ComboBoxItem Content="요약"/>
                                     <ComboBoxItem Content="번역"/>
                                     <ComboBoxItem Content="교정"/>
@@ -211,8 +208,18 @@
                                 <TextBlock x:Name="AiTaskHint" Margin="0,6,0,0"
                                            Style="{StaticResource FsCaptionStyle}"
                                            Text="텍스트(txt·md·docx) 출력 시 LLM이 적용합니다"/>
-                                <StackPanel x:Name="AiTargetLangPanel" Margin="0,10,0,0"
+                                <StackPanel x:Name="AiTargetLangPanel" Margin="0,10,0,0">
-                                            Visibility="Collapsed">
+                                    <StackPanel.Style>
+                                        <Style TargetType="StackPanel">
+                                            <Setter Property="Visibility" Value="Collapsed"/>
+                                            <Style.Triggers>
+                                                <!-- 번역(인덱스 1)일 때만 대상 언어 입력 표시 -->
+                                                <DataTrigger Binding="{Binding SelectedIndex, ElementName=AiTaskCombo}" Value="1">
+                                                    <Setter Property="Visibility" Value="Visible"/>
+                                                </DataTrigger>
+                                            </Style.Triggers>
+                                        </Style>
+                                    </StackPanel.Style>
                                     <TextBlock Text="대상 언어" Style="{StaticResource FsCaptionStyle}"
                                                Margin="0,0,0,4"/>
                                     <TextBox x:Name="AiTargetLangBox"
@@ -338,7 +345,8 @@
                             <StackPanel Orientation="Horizontal">
                                 <ToggleButton x:Name="TabActiveBtn"
                                               Style="{StaticResource FsTabPillStyle}"
-                                              Click="OnTabClick" Tag="Active">
+                                              Command="{Binding TabCommand, RelativeSource={RelativeSource AncestorType=Window}}"
+                                              CommandParameter="Active">
                                     <StackPanel Orientation="Horizontal">
                                         <TextBlock Text="Active Queue" VerticalAlignment="Center"/>
                                         <Border Margin="8,0,0,0" Style="{StaticResource FsTabBadgeStyle}">
@@ -351,7 +359,8 @@
                                 <ToggleButton x:Name="TabPastBtn" Margin="8,0,0,0"
                                               IsChecked="True"
                                               Style="{StaticResource FsTabPillStyle}"
-                                              Click="OnTabClick" Tag="Past">
+                                              Command="{Binding TabCommand, RelativeSource={RelativeSource AncestorType=Window}}"
+                                              CommandParameter="Past">
                                     <StackPanel Orientation="Horizontal">
                                         <TextBlock Text="Past Results" VerticalAlignment="Center"/>
                                         <Border Margin="8,0,0,0" Style="{StaticResource FsTabBadgeStyle}">

src/Everything2Everything.App/Views/MainWindow.xaml.cs

@@ -50,6 +50,9 @@ public partial class MainWindow : Wpf.Ui.Controls.FluentWindow
     public ICommand PreviewOpenFolderCommand { get; }
     public ICommand RemoveQueueItemCommand { get; }
     public ICommand OpenFolderCommand { get; }
+    public ICommand TabCommand { get; }
+    public ICommand ConflictRuleCommand { get; }
+    public ICommand CombineToggleCommand { get; }
 
     public MainWindow(ConversionEngine engine, ISettingsStore settings, IReadOnlyList<string>? initialFiles = null)
     {
@@ -72,6 +75,9 @@ public partial class MainWindow : Wpf.Ui.Controls.FluentWindow
         PreviewOpenFolderCommand = new RelayCommand(_ => OnPreviewOpenFolder(this, new RoutedEventArgs()));
         RemoveQueueItemCommand = new RelayCommand(p => RemoveQueueItem(p as QueueItem));
         OpenFolderCommand = new RelayCommand(p => OpenFolderForPath(p as string));
+        TabCommand = new RelayCommand(p => ShowTab(p as string ?? "Past"));
+        ConflictRuleCommand = new RelayCommand(p => SetConflictRule(p as string));
+        CombineToggleCommand = new RelayCommand(_ => UpdateCombineState(SelectedOutputExtension));
 
         InitializeComponent();
 
@@ -147,14 +153,6 @@ public partial class MainWindow : Wpf.Ui.Controls.FluentWindow
 
     // ============== Tabs ==============
 
-    private void OnTabClick(object sender, RoutedEventArgs e)
-    {
-        if (sender is ToggleButton tb && tb.Tag is string tag)
-        {
-            ShowTab(tag);
-        }
-    }
-
     private void ShowTab(string tag)
     {
         TabActiveBtn.IsChecked = tag == "Active";
@@ -270,32 +268,18 @@ public partial class MainWindow : Wpf.Ui.Controls.FluentWindow
 
     // ============== Sidebar inputs ==============
 
-    private void OnQualityChanged(object sender, RoutedPropertyChangedEventArgs<double> e)
+    private void SetConflictRule(string? tag)
     {
-        if (QualityValueText is null) return;
+        _conflictRule = tag switch
-        QualityValueText.Text = $"{(int)e.NewValue}%";
-    }
-
-    private void OnConflictSegmentClick(object sender, RoutedEventArgs e)
-    {
-        if (sender is not ToggleButton clicked) return;
-        ConflictSkipBtn.IsChecked = clicked == ConflictSkipBtn;
-        ConflictRenameBtn.IsChecked = clicked == ConflictRenameBtn;
-        ConflictReplaceBtn.IsChecked = clicked == ConflictReplaceBtn;
-        _conflictRule = (clicked.Tag as string) switch
         {
             "Skip" => NameCollision.Skip,
             "Replace" => NameCollision.Overwrite,
             _ => NameCollision.AppendNumber,
         };
-    }
+        // 세그먼트 토글 그룹의 상호배제(하나만 체크).
-
+        ConflictSkipBtn.IsChecked = tag == "Skip";
-    private void OnAiTaskChanged(object sender, SelectionChangedEventArgs e)
+        ConflictRenameBtn.IsChecked = tag == "Rename";
-    {
+        ConflictReplaceBtn.IsChecked = tag == "Replace";
-        // 번역(인덱스 1)일 때만 대상 언어 입력을 표시
-        if (AiTargetLangPanel is null) return;
-        AiTargetLangPanel.Visibility =
-            (AiTaskCombo?.SelectedIndex == 1) ? Visibility.Visible : Visibility.Collapsed;
     }
 
     private void OnPickOutputFolderClick(object sender, RoutedEventArgs e)
@@ -1052,11 +1036,6 @@ public partial class MainWindow : Wpf.Ui.Controls.FluentWindow
         };
     }
 
-    private void OnCombineToggleChanged(object sender, RoutedEventArgs e)
-    {
-        UpdateCombineState(SelectedOutputExtension);
-    }
-
     private void OnOutputFormatChanged(object sender, SelectionChangedEventArgs e)
     {
         if (_suppressFormatChanged) return;