UI: borderless window with custom chrome, default 1280x720

Window
------
- Default size 1280x720 (16:9 widescreen — matches the screenshot framing
  the user requested), MinWidth=980 MinHeight=600.
- WindowStyle=None + ResizeMode=CanResize: drop the OS title bar but
  keep edge resize.
- WindowChrome: CaptionHeight=56 makes the top bar Border the
  drag-handle for moving the window. ResizeBorderThickness=6 gives
  6px of grab area on each edge, GlassFrameThickness=0 disables Aero.

Custom chrome buttons
---------------------
Three new style keys in Theme.xaml:
- WindowControlButton: 46x32 transparent button, hovers at #FFFFFF22
  (semi-translucent white) — used for minimize and maximize/restore.
- WindowCloseButton: same shape, hovers at #E81123 (Win11 red).

Three handlers wired up: OnMinimizeClick, OnMaxRestoreClick, OnCloseClick.

Caption click-through
---------------------
WindowChrome reserves the caption area for window dragging by default —
buttons inside it would otherwise feel "dead". Each interactive control
in the top bar (Vérifier les MAJ / Dossier / License pill / Activer /
Paramètres / min / max / close) gets
shell:WindowChrome.IsHitTestVisibleInChrome="True" so clicks reach the
button instead of starting a drag. The text/logo region remains
draggable.

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

src/PSLauncher.App/Views/MainWindow.xaml

@@ -2,16 +2,28 @@
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:vm="clr-namespace:PSLauncher.App.ViewModels"
+        xmlns:shell="clr-namespace:System.Windows.Shell;assembly=PresentationFramework"
         Title="PROSERVE Launcher"
         Background="Black"
-        Width="980" Height="780"
-        MinWidth="780" MinHeight="500"
+        Width="1280" Height="720"
+        MinWidth="980" MinHeight="600"
         WindowStartupLocation="CenterScreen"
+        WindowStyle="None"
+        ResizeMode="CanResize"
+        AllowsTransparency="False"
         d:DataContext="{d:DesignInstance Type=vm:MainViewModel}"
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
         mc:Ignorable="d"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006">
 
+    <shell:WindowChrome.WindowChrome>
+        <shell:WindowChrome CaptionHeight="56"
+                            GlassFrameThickness="0"
+                            CornerRadius="0"
+                            ResizeBorderThickness="6"
+                            UseAeroCaptionButtons="False" />
+    </shell:WindowChrome.WindowChrome>
+
     <Window.Resources>
 
         <!-- =================== TEMPLATE : LIGNE COMPACTE (autres versions) =================== -->
@@ -185,10 +197,12 @@
                     <Button Style="{StaticResource SecondaryButton}"
                             Content="🔄  Vérifier les MAJ"
                             Command="{Binding CheckForUpdatesCommand}"
+                            shell:WindowChrome.IsHitTestVisibleInChrome="True"
                             Margin="0,0,8,0" />
                     <Button Style="{StaticResource SecondaryButton}"
                             Content="📁  Dossier"
                             Command="{Binding OpenInstallRootCommand}"
+                            shell:WindowChrome.IsHitTestVisibleInChrome="True"
                             Margin="0,0,12,0" />
                     <!-- Badge license -->
                     <Border CornerRadius="14" Padding="10,4"
@@ -256,10 +270,27 @@
                     <Button Style="{StaticResource SecondaryButton}"
                             Content="🔑  Activer / changer"
                             Command="{Binding ActivateLicenseCommand}"
+                            shell:WindowChrome.IsHitTestVisibleInChrome="True"
                             Margin="0,0,8,0" />
                     <Button Style="{StaticResource SecondaryButton}"
                             Content="⚙  Paramètres"
-                            Command="{Binding OpenSettingsCommand}" />
+                            shell:WindowChrome.IsHitTestVisibleInChrome="True"
+                            Command="{Binding OpenSettingsCommand}"
+                            Margin="0,0,16,0" />
+
+                    <!-- Window controls custom (style chrome dark) -->
+                    <Button Style="{StaticResource WindowControlButton}"
+                            Content="—" ToolTip="Réduire"
+                            shell:WindowChrome.IsHitTestVisibleInChrome="True"
+                            Click="OnMinimizeClick" />
+                    <Button Style="{StaticResource WindowControlButton}"
+                            Content="☐" ToolTip="Agrandir / Restaurer"
+                            shell:WindowChrome.IsHitTestVisibleInChrome="True"
+                            Click="OnMaxRestoreClick" />
+                    <Button Style="{StaticResource WindowCloseButton}"
+                            Content="✕" ToolTip="Fermer"
+                            shell:WindowChrome.IsHitTestVisibleInChrome="True"
+                            Click="OnCloseClick" />
                 </StackPanel>
             </Grid>
         </Border>