Right sidebar nav: Library / Reports / Documentation tabs (WebView2)

The body of the launcher is now a 2-column layout:
- Left : swappable content area
- Right (200px) : sidebar with 3 nav buttons + active-state highlighting

Three pages, all under the same window chrome / footer:

1. **Library** (default) — the existing main view (featured version,
   other versions list, floating "Vérifier les MAJ" button, copyright).
2. **Reports** — embedded WebView2 navigated to a configurable URL.
   Default http://localhost/ProserveReport/ which matches the local
   stats tool installed on each customer machine alongside XAMPP.
3. **Documentation** — WebView2 with a configurable URL, falls back
   to a placeholder explaining where to set it if empty.

Implementation
- LocalConfig gains ReportUrl + DocumentationUrl (string).
- MainViewModel gains LauncherPage enum + CurrentPage state with
  Navigate{Library,Report,Documentation}Command. ReportUri /
  DocumentationUri parse the strings to Uri for WebView2.Source.
- Theme.xaml: NavButton style (transparent, left-aligned, hover
  darken, active state highlighted via Tag bool + accent left-border).
- InverseBoolToVisibilityConverter added (true → Collapsed) for the
  documentation placeholder fallback.
- Microsoft.Web.WebView2 NuGet (1.0.2792.45). Runtime is pre-installed
  on Win11 and auto-pushed via Windows Update on Win10. If absent,
  WebView2 surfaces an error which the user sees inline.
- Settings → Avancés → Serveur extended with the two URL fields.
- Strings.cs: NavLibrary / NavReport / NavDocumentation,
  SettingsReportUrl / SettingsDocsUrl, DocsPlaceholder, WebViewLoadError.
  Sidebar localized in 5 languages.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/PSLauncher.App/Views/MainWindow.xaml

@@ -4,6 +4,7 @@
         xmlns:vm="clr-namespace:PSLauncher.App.ViewModels"
         xmlns:loc="clr-namespace:PSLauncher.Core.Localization;assembly=PSLauncher.Core"
         xmlns:shell="clr-namespace:System.Windows.Shell;assembly=PresentationFramework"
+        xmlns:wv2="clr-namespace:Microsoft.Web.WebView2.Wpf;assembly=Microsoft.Web.WebView2.Wpf"
         Title="PROSERVE Launcher"
         Icon="pack://application:,,,/Resources/favicon.ico"
         Background="Black"
@@ -315,8 +316,23 @@
             </Grid>
         </Border>
 
-        <!-- Body : Grid pour pouvoir superposer le bouton flottant "Vérifier les MAJ" -->
+        <!--
+            Body : grid 2 colonnes — content area swap-pable à gauche, sidebar de
+            navigation fixe à droite. Le content area lui-même est un Grid qui
+            superpose plusieurs blocs (Library / Report / Documentation) gérés
+            par leur Visibility liée à CurrentPage.
+        -->
         <Grid Grid.Row="1">
+            <Grid.ColumnDefinitions>
+                <ColumnDefinition Width="*" />
+                <ColumnDefinition Width="200" />
+            </Grid.ColumnDefinitions>
+
+            <!-- ============== Content area (col 0, swap par CurrentPage) ============== -->
+            <Grid Grid.Column="0">
+
+            <!-- ====================== LIBRARY PAGE ====================== -->
+            <Grid Visibility="{Binding IsLibrary, Converter={StaticResource BoolToVisibility}}">
             <ScrollViewer VerticalScrollBarVisibility="Auto">
             <StackPanel Margin="32,28">
 
@@ -547,6 +563,67 @@
                            FontSize="11"
                            Foreground="White" />
             </Border>
+            </Grid>
+            <!-- ====================== END LIBRARY PAGE ====================== -->
+
+            <!-- ====================== REPORT PAGE (WebView2) ====================== -->
+            <Grid Background="{StaticResource Brush.Bg.Window}"
+                  Visibility="{Binding IsReport, Converter={StaticResource BoolToVisibility}}">
+                <wv2:WebView2 x:Name="ReportWebView"
+                              Source="{Binding ReportUri, Mode=OneWay}" />
+            </Grid>
+
+            <!-- ====================== DOCUMENTATION PAGE ====================== -->
+            <Grid Background="{StaticResource Brush.Bg.Window}"
+                  Visibility="{Binding IsDocumentation, Converter={StaticResource BoolToVisibility}}">
+                <!-- WebView2 si une URL est configurée, sinon un placeholder explicatif -->
+                <wv2:WebView2 x:Name="DocsWebView"
+                              Source="{Binding DocumentationUri, Mode=OneWay}"
+                              Visibility="{Binding HasDocumentationUrl, Converter={StaticResource BoolToVisibility}}" />
+                <TextBlock Text="{x:Static loc:Strings.DocsPlaceholder}"
+                           HorizontalAlignment="Center" VerticalAlignment="Center"
+                           Foreground="{StaticResource Brush.Text.Secondary}"
+                           FontSize="14" TextAlignment="Center" TextWrapping="Wrap"
+                           MaxWidth="500"
+                           Visibility="{Binding HasDocumentationUrl, Converter={StaticResource InverseBoolToVisibility}}" />
+            </Grid>
+
+            </Grid>
+            <!-- ============== END Content area ============== -->
+
+            <!-- ============== Right sidebar : nav buttons ============== -->
+            <Border Grid.Column="1"
+                    Background="#0A0A0E"
+                    BorderBrush="{StaticResource Brush.Border}"
+                    BorderThickness="1,0,0,0">
+                <StackPanel Orientation="Vertical" Margin="0,16,0,0">
+                    <!-- Style des boutons définis dans Theme.xaml (NavButton) -->
+                    <Button Style="{StaticResource NavButton}"
+                            Command="{Binding NavigateLibraryCommand}"
+                            Tag="{Binding IsLibrary}">
+                        <StackPanel Orientation="Horizontal">
+                            <TextBlock Text="📚" FontSize="16" Margin="0,0,12,0" VerticalAlignment="Center" />
+                            <TextBlock Text="{x:Static loc:Strings.NavLibrary}" VerticalAlignment="Center" />
+                        </StackPanel>
+                    </Button>
+                    <Button Style="{StaticResource NavButton}"
+                            Command="{Binding NavigateReportCommand}"
+                            Tag="{Binding IsReport}">
+                        <StackPanel Orientation="Horizontal">
+                            <TextBlock Text="📊" FontSize="16" Margin="0,0,12,0" VerticalAlignment="Center" />
+                            <TextBlock Text="{x:Static loc:Strings.NavReport}" VerticalAlignment="Center" />
+                        </StackPanel>
+                    </Button>
+                    <Button Style="{StaticResource NavButton}"
+                            Command="{Binding NavigateDocumentationCommand}"
+                            Tag="{Binding IsDocumentation}">
+                        <StackPanel Orientation="Horizontal">
+                            <TextBlock Text="📖" FontSize="16" Margin="0,0,12,0" VerticalAlignment="Center" />
+                            <TextBlock Text="{x:Static loc:Strings.NavDocumentation}" VerticalAlignment="Center" />
+                        </StackPanel>
+                    </Button>
+                </StackPanel>
+            </Border>
         </Grid>
 
         <!-- Footer : visible uniquement quand busy / status à afficher.