Copyright: readable pill with proper "© 2026 ASTERION VR — All rights reserved"

The previous copyright was a faded TextBlock at Opacity 0.7 with the
secondary grey color, sitting directly on top of the variable-
luminance background image. Hard to read on the bright spots of the
ASTERION VR engraving.

Wrap it in a Border with #A0000000 background (~63% opacity black)
and CornerRadius=10 — same pill style as the license badge — so the
text reads cleanly regardless of what's behind. Foreground is now
plain white instead of the secondary grey.

Text changed from the terse "© ASTERION VR" to the proper convention:
- UI: "© 2026 ASTERION VR — Tous droits réservés" (matches the
  French-language UI in MainWindow + Settings)
- Assembly metadata (Properties → Détails on the .exe): English form
  "© 2026 ASTERION VR — All rights reserved"

Same change applied to PSLauncher.Updater.csproj.

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

src/PSLauncher.App/Views/MainWindow.xaml

@@ -496,13 +496,17 @@
                     Content="🔄  Vérifier les MAJ"
                     Command="{Binding CheckForUpdatesCommand}" />
 
-            <!-- Copyright flottant en bas-droite, discret -->
-            <TextBlock HorizontalAlignment="Right" VerticalAlignment="Bottom"
-                       Margin="0,0,32,28"
-                       Text="© ASTERION VR"
-                       FontSize="11"
-                       Foreground="{StaticResource Brush.Text.Secondary}"
-                       Opacity="0.7" />
+            <!-- Copyright flottant en bas-droite, sur une pill sombre pour rester
+                 lisible quel que soit l'arrière-plan (image, voile noir, etc.). -->
+            <Border HorizontalAlignment="Right" VerticalAlignment="Bottom"
+                    Margin="0,0,32,28"
+                    Background="#A0000000"
+                    CornerRadius="10"
+                    Padding="10,4">
+                <TextBlock Text="© 2026 ASTERION VR — Tous droits réservés"
+                           FontSize="11"
+                           Foreground="White" />
+            </Border>
         </Grid>
 
         <!-- Footer : visible uniquement quand busy / status à afficher.