feat(14-02): add directory browse mode UI with mode toggle, DataGrid, and loading UX

- Mode toggle (Search/Browse) RadioButtons at top of left panel
- Search panel uses DataTrigger inverse visibility (collapses when IsBrowseMode=true)
- Browse panel with Load/Cancel buttons, IncludeGuests checkbox, filter TextBox, status/count
- Directory DataGrid with 5 columns (Name, Email, Department, Job Title, Type)
- Guest users highlighted in orange via DataTrigger on UserType
- SelectedUsers extracted to shared section visible in both modes
- DataGrid wired to DirectoryDataGrid_MouseDoubleClick handler
- Scan Options and Run/Export buttons remain always visible

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

SharepointToolbox/Views/Tabs/UserAccessAuditView.xaml

@@ -15,8 +15,30 @@
     <!-- Left panel -->
     <DockPanel Grid.Column="0" Grid.Row="0" Margin="8">
 
-      <GroupBox Header="{Binding Source={x:Static loc:TranslationSource.Instance}, Path=[audit.grp.users]}"
+      <!-- Mode toggle -->
-                DockPanel.Dock="Top" Margin="0,0,0,8" Padding="8">
+      <StackPanel DockPanel.Dock="Top" Orientation="Horizontal" Margin="0,0,0,8">
+        <RadioButton Content="{Binding Source={x:Static loc:TranslationSource.Instance}, Path=[audit.mode.search]}"
+                     IsChecked="{Binding IsBrowseMode, Converter={StaticResource InverseBoolConverter}}"
+                     Margin="0,0,12,0" />
+        <RadioButton Content="{Binding Source={x:Static loc:TranslationSource.Instance}, Path=[audit.mode.browse]}"
+                     IsChecked="{Binding IsBrowseMode}" />
+      </StackPanel>
+
+      <!-- SEARCH MODE PANEL (visible when IsBrowseMode=false) -->
+      <GroupBox DockPanel.Dock="Top" Margin="0,0,0,8" Padding="8">
+        <GroupBox.Header>
+          <TextBlock Text="{Binding Source={x:Static loc:TranslationSource.Instance}, Path=[audit.grp.users]}" />
+        </GroupBox.Header>
+        <GroupBox.Style>
+          <Style TargetType="GroupBox">
+            <Setter Property="Visibility" Value="Visible" />
+            <Style.Triggers>
+              <DataTrigger Binding="{Binding IsBrowseMode}" Value="True">
+                <Setter Property="Visibility" Value="Collapsed" />
+              </DataTrigger>
+            </Style.Triggers>
+          </Style>
+        </GroupBox.Style>
         <StackPanel>
           <TextBox Text="{Binding SearchQuery, UpdateSourceTrigger=PropertyChanged}" Margin="0,0,0,2" />
           <TextBlock Text="Searching..." FontStyle="Italic" FontSize="10" Foreground="Gray" Margin="0,0,0,2">
@@ -57,26 +79,124 @@
               </DataTemplate>
             </ListBox.ItemTemplate>
           </ListBox>
-          <ItemsControl ItemsSource="{Binding SelectedUsers}" Margin="0,0,0,4">
-            <ItemsControl.ItemTemplate>
-              <DataTemplate>
-                <Border Background="#EBF5FB" BorderBrush="#2980B9" BorderThickness="1"
-                        CornerRadius="4" Padding="6,2" Margin="0,1">
-                  <DockPanel>
-                    <Button Content="x" DockPanel.Dock="Right" Padding="4,0"
-                            Background="Transparent" BorderThickness="0"
-                            Command="{Binding DataContext.RemoveUserCommand, RelativeSource={RelativeSource AncestorType=ItemsControl}}"
-                            CommandParameter="{Binding}" />
-                    <TextBlock Text="{Binding DisplayName}" VerticalAlignment="Center" />
-                  </DockPanel>
-                </Border>
-              </DataTemplate>
-            </ItemsControl.ItemTemplate>
-          </ItemsControl>
-          <TextBlock Text="{Binding SelectedUsersLabel}" FontStyle="Italic" Foreground="Gray" FontSize="10" />
         </StackPanel>
       </GroupBox>
 
+      <!-- BROWSE MODE PANEL (visible when IsBrowseMode=true) -->
+      <GroupBox DockPanel.Dock="Top" Margin="0,0,0,8" Padding="8"
+                Visibility="{Binding IsBrowseMode, Converter={StaticResource BoolToVisibilityConverter}}">
+        <GroupBox.Header>
+          <TextBlock Text="{Binding Source={x:Static loc:TranslationSource.Instance}, Path=[directory.grp.browse]}" />
+        </GroupBox.Header>
+        <DockPanel>
+          <!-- Load/Cancel buttons -->
+          <Grid DockPanel.Dock="Top" Margin="0,0,0,4">
+            <Grid.ColumnDefinitions>
+              <ColumnDefinition Width="*" />
+              <ColumnDefinition Width="*" />
+            </Grid.ColumnDefinitions>
+            <Button Grid.Column="0"
+                    Content="{Binding Source={x:Static loc:TranslationSource.Instance}, Path=[directory.btn.load]}"
+                    Command="{Binding LoadDirectoryCommand}" Margin="0,0,4,0" Padding="6,3" />
+            <Button Grid.Column="1"
+                    Content="{Binding Source={x:Static loc:TranslationSource.Instance}, Path=[directory.btn.cancel]}"
+                    Command="{Binding CancelDirectoryLoadCommand}" Padding="6,3" />
+          </Grid>
+
+          <!-- Include guests checkbox -->
+          <CheckBox DockPanel.Dock="Top"
+                    Content="{Binding Source={x:Static loc:TranslationSource.Instance}, Path=[directory.chk.guests]}"
+                    IsChecked="{Binding IncludeGuests}" Margin="0,0,0,4" />
+
+          <!-- Filter text -->
+          <TextBox DockPanel.Dock="Top"
+                   Text="{Binding DirectoryFilterText, UpdateSourceTrigger=PropertyChanged}"
+                   Margin="0,0,0,4" />
+
+          <!-- Status row: load status + user count -->
+          <StackPanel DockPanel.Dock="Top" Orientation="Horizontal" Margin="0,0,0,4">
+            <TextBlock Text="{Binding DirectoryLoadStatus}" FontStyle="Italic" Foreground="Gray" FontSize="10"
+                       Margin="0,0,8,0" />
+            <TextBlock FontSize="10" Foreground="Gray">
+              <TextBlock.Text>
+                <MultiBinding StringFormat="{}{0} {1}">
+                  <Binding Path="DirectoryUserCount" />
+                  <Binding Source="{x:Static loc:TranslationSource.Instance}" Path="[directory.status.count]" />
+                </MultiBinding>
+              </TextBlock.Text>
+            </TextBlock>
+          </StackPanel>
+
+          <!-- Hint text -->
+          <TextBlock DockPanel.Dock="Bottom"
+                     Text="{Binding Source={x:Static loc:TranslationSource.Instance}, Path=[directory.hint.doubleclick]}"
+                     FontStyle="Italic" Foreground="Gray" FontSize="10" Margin="0,4,0,0"
+                     TextWrapping="Wrap" />
+
+          <!-- Directory DataGrid -->
+          <DataGrid x:Name="DirectoryDataGrid"
+                    ItemsSource="{Binding DirectoryUsersView}"
+                    AutoGenerateColumns="False" IsReadOnly="True"
+                    VirtualizingPanel.IsVirtualizing="True" EnableRowVirtualization="True"
+                    MouseDoubleClick="DirectoryDataGrid_MouseDoubleClick"
+                    CanUserSortColumns="True"
+                    SelectionMode="Single" SelectionUnit="FullRow"
+                    HeadersVisibility="Column" GridLinesVisibility="Horizontal"
+                    BorderThickness="1" BorderBrush="#DDDDDD">
+            <DataGrid.Columns>
+              <DataGridTextColumn Header="Name"
+                                  Binding="{Binding DisplayName}" Width="120" />
+              <DataGridTextColumn Header="Email"
+                                  Binding="{Binding UserPrincipalName}" Width="140" />
+              <DataGridTextColumn Header="Department"
+                                  Binding="{Binding Department}" Width="90" />
+              <DataGridTextColumn Header="Job Title"
+                                  Binding="{Binding JobTitle}" Width="90" />
+              <DataGridTemplateColumn Header="Type" Width="60">
+                <DataGridTemplateColumn.CellTemplate>
+                  <DataTemplate>
+                    <TextBlock Text="{Binding UserType}" VerticalAlignment="Center">
+                      <TextBlock.Style>
+                        <Style TargetType="TextBlock">
+                          <Style.Triggers>
+                            <DataTrigger Binding="{Binding UserType}" Value="Guest">
+                              <Setter Property="Foreground" Value="#F39C12" />
+                              <Setter Property="FontWeight" Value="SemiBold" />
+                            </DataTrigger>
+                          </Style.Triggers>
+                        </Style>
+                      </TextBlock.Style>
+                    </TextBlock>
+                  </DataTemplate>
+                </DataGridTemplateColumn.CellTemplate>
+              </DataGridTemplateColumn>
+            </DataGrid.Columns>
+          </DataGrid>
+        </DockPanel>
+      </GroupBox>
+
+      <!-- SHARED: Selected users (visible in both modes) -->
+      <StackPanel DockPanel.Dock="Top" Margin="0,0,0,8">
+        <ItemsControl ItemsSource="{Binding SelectedUsers}" Margin="0,0,0,4">
+          <ItemsControl.ItemTemplate>
+            <DataTemplate>
+              <Border Background="#EBF5FB" BorderBrush="#2980B9" BorderThickness="1"
+                      CornerRadius="4" Padding="6,2" Margin="0,1">
+                <DockPanel>
+                  <Button Content="x" DockPanel.Dock="Right" Padding="4,0"
+                          Background="Transparent" BorderThickness="0"
+                          Command="{Binding DataContext.RemoveUserCommand, RelativeSource={RelativeSource AncestorType=ItemsControl}}"
+                          CommandParameter="{Binding}" />
+                  <TextBlock Text="{Binding DisplayName}" VerticalAlignment="Center" />
+                </DockPanel>
+              </Border>
+            </DataTemplate>
+          </ItemsControl.ItemTemplate>
+        </ItemsControl>
+        <TextBlock Text="{Binding SelectedUsersLabel}" FontStyle="Italic" Foreground="Gray" FontSize="10" />
+      </StackPanel>
+
+      <!-- Scan Options (always visible) -->
       <GroupBox Header="{Binding Source={x:Static loc:TranslationSource.Instance}, Path=[audit.grp.options]}"
                 DockPanel.Dock="Top" Margin="0,0,0,8" Padding="8">
         <StackPanel>
@@ -89,6 +209,7 @@
         </StackPanel>
       </GroupBox>
 
+      <!-- Run/Export buttons (always visible) -->
       <StackPanel DockPanel.Dock="Top">
         <Grid Margin="0,0,0,4">
           <Grid.ColumnDefinitions>