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/SettingsDialog.xaml

@@ -213,6 +213,23 @@
                         <TextBlock Text="{Binding ConnectionStatus}"
                                    Foreground="{StaticResource Brush.Text.Secondary}"
                                    FontSize="12" Margin="0,8,0,0" TextWrapping="Wrap" />
+
+                        <!-- URLs des onglets latéraux Report / Documentation -->
+                        <TextBlock Text="{x:Static loc:Strings.SettingsReportUrl}"
+                                   Foreground="{StaticResource Brush.Text.Secondary}"
+                                   FontSize="12" Margin="0,16,0,4" />
+                        <TextBox Text="{Binding ReportUrl, UpdateSourceTrigger=PropertyChanged}"
+                                 Background="#1A1A20" Foreground="{StaticResource Brush.Text.Primary}"
+                                 BorderBrush="{StaticResource Brush.Border}" BorderThickness="1" Padding="8"
+                                 FontFamily="Consolas" />
+
+                        <TextBlock Text="{x:Static loc:Strings.SettingsDocsUrl}"
+                                   Foreground="{StaticResource Brush.Text.Secondary}"
+                                   FontSize="12" Margin="0,12,0,4" />
+                        <TextBox Text="{Binding DocumentationUrl, UpdateSourceTrigger=PropertyChanged}"
+                                 Background="#1A1A20" Foreground="{StaticResource Brush.Text.Primary}"
+                                 BorderBrush="{StaticResource Brush.Border}" BorderThickness="1" Padding="8"
+                                 FontFamily="Consolas" />
                     </StackPanel>
                 </Border>