feat(ui): chromeless title bar with custom caption controls

MainWindow drops the standard Windows title bar (WindowStyle=None + WindowChrome with CaptionHeight=44, ResizeBorderThickness=6, UseAeroCaptionButtons=False) and draws its own minimize / maximize-restore / close buttons inline in the existing header strip. The custom buttons opt into shell:WindowChrome.IsHitTestVisibleInChrome=True so clicks fire on them rather than starting a window drag.

Result: the entire top of the window is now ours, matching the Microsoft Teams desktop client's flush header look. The 'TeamsISO + by Wild Dragon' branding sits at the same baseline as the engine-status pill and the caption controls, and dragging anywhere not occupied by an interactive widget moves the window.

Caption-button styles in the theme: 46x32 hover-tinted, with the close button turning the Windows 11 #C42B1C red on hover. Maximize-button glyph swaps between the single-rectangle and overlapping-rectangles variants on StateChanged.

Drive-by: ParticipantViewModel.{FramesIn,FramesOut,IncomingResolution} setters dropped from private to public so {Run Text=...} bindings (which default to TwoWay on Run) can attach without WPF throwing 'cannot work on read-only property'.

src/TeamsISO.App/MainWindow.xaml

@@ -3,14 +3,33 @@
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:vm="clr-namespace:TeamsISO.App.ViewModels"
         xmlns:conv="clr-namespace:TeamsISO.App.Converters"
+        xmlns:shell="clr-namespace:System.Windows.Shell;assembly=PresentationFramework"
         Title="TeamsISO"
         Height="780" Width="1280"
         MinHeight="640" MinWidth="1080"
         Background="{DynamicResource Wd.Canvas}"
+        WindowStyle="None"
+        ResizeMode="CanResize"
         UseLayoutRounding="True"
         TextOptions.TextFormattingMode="Ideal"
         TextOptions.TextRenderingMode="ClearType">
 
+    <!--
+        Chromeless window chrome — removes the standard Windows title bar so we can
+        draw our own header that matches the Teams flush look. CaptionHeight=44 makes
+        the top 44px of the window act as a drag region. ResizeBorderThickness=6
+        keeps edge-resize working. UseAeroCaptionButtons=False disables the OS-drawn
+        min/max/close (we draw our own).
+    -->
+    <shell:WindowChrome.WindowChrome>
+        <shell:WindowChrome
+            CaptionHeight="44"
+            ResizeBorderThickness="6"
+            CornerRadius="0"
+            GlassFrameThickness="0"
+            UseAeroCaptionButtons="False"/>
+    </shell:WindowChrome.WindowChrome>
+
     <Window.Resources>
         <conv:BoolToVisibilityConverter x:Key="BoolToVis"/>
         <conv:EnumDescriptionConverter x:Key="EnumDesc"/>
@@ -168,21 +187,66 @@
                         </Border>
                     </StackPanel>
 
-                    <Border Grid.Column="1"
-                            Style="{StaticResource Wd.Pill}"
-                            Background="{DynamicResource Wd.Status.LiveBg}"
-                            VerticalAlignment="Center">
-                        <StackPanel Orientation="Horizontal">
-                            <Ellipse Width="7" Height="7"
-                                     Fill="{DynamicResource Wd.Status.Live}"
-                                     VerticalAlignment="Center"/>
-                            <TextBlock Text="{Binding StatusText}"
-                                       Style="{StaticResource Wd.Text.Body}"
-                                       FontSize="12"
-                                       Margin="8,0,0,0"
-                                       VerticalAlignment="Center"/>
-                        </StackPanel>
-                    </Border>
+                    <StackPanel Grid.Column="1"
+                                Orientation="Horizontal"
+                                VerticalAlignment="Center">
+                        <Border Style="{StaticResource Wd.Pill}"
+                                Background="{DynamicResource Wd.Status.LiveBg}"
+                                VerticalAlignment="Center"
+                                Margin="0,0,16,0">
+                            <StackPanel Orientation="Horizontal">
+                                <Ellipse Width="7" Height="7"
+                                         Fill="{DynamicResource Wd.Status.Live}"
+                                         VerticalAlignment="Center"/>
+                                <TextBlock Text="{Binding StatusText}"
+                                           Style="{StaticResource Wd.Text.Body}"
+                                           FontSize="12"
+                                           Margin="8,0,0,0"
+                                           VerticalAlignment="Center"/>
+                            </StackPanel>
+                        </Border>
+
+                        <!--
+                            Custom window control buttons. WindowChrome.IsHitTestVisibleInChrome
+                            tells the chrome that clicks here are real clicks, not drag-region
+                            clicks, so the buttons fire instead of starting a window drag.
+                        -->
+                        <Button x:Name="MinimizeButton"
+                                Style="{StaticResource Wd.Button.Caption}"
+                                Click="OnMinimize"
+                                shell:WindowChrome.IsHitTestVisibleInChrome="True"
+                                ToolTip="Minimize">
+                            <Path Data="M 0,5 L 10,5"
+                                  Stroke="{DynamicResource Wd.Text.Primary}"
+                                  StrokeThickness="1.2"
+                                  Width="10" Height="10"
+                                  Stretch="None"/>
+                        </Button>
+                        <Button x:Name="MaximizeButton"
+                                Style="{StaticResource Wd.Button.Caption}"
+                                Click="OnMaximizeRestore"
+                                shell:WindowChrome.IsHitTestVisibleInChrome="True"
+                                ToolTip="Maximize">
+                            <Path x:Name="MaximizeIcon"
+                                  Data="M 0,0 L 10,0 L 10,10 L 0,10 Z"
+                                  Stroke="{DynamicResource Wd.Text.Primary}"
+                                  StrokeThickness="1.2"
+                                  Fill="Transparent"
+                                  Width="10" Height="10"
+                                  Stretch="None"/>
+                        </Button>
+                        <Button x:Name="CloseButton"
+                                Style="{StaticResource Wd.Button.CaptionClose}"
+                                Click="OnClose"
+                                shell:WindowChrome.IsHitTestVisibleInChrome="True"
+                                ToolTip="Close">
+                            <Path Data="M 0,0 L 10,10 M 10,0 L 0,10"
+                                  Stroke="{DynamicResource Wd.Text.Primary}"
+                                  StrokeThickness="1.2"
+                                  Width="10" Height="10"
+                                  Stretch="None"/>
+                        </Button>
+                    </StackPanel>
                 </Grid>
             </Border>
 

src/TeamsISO.App/MainWindow.xaml.cs

@@ -1,4 +1,5 @@
 using System.Windows;
+using System.Windows.Shapes;
 using TeamsISO.App.ViewModels;
 
 namespace TeamsISO.App;
@@ -8,10 +9,37 @@ public partial class MainWindow : Window
     public MainWindow()
     {
         InitializeComponent();
+        StateChanged += OnWindowStateChanged;
     }
 
     public MainWindow(MainViewModel viewModel) : this()
     {
         DataContext = viewModel;
     }
+
+    /// <summary>Custom min button — chrome'd window has no system caption buttons.</summary>
+    private void OnMinimize(object sender, RoutedEventArgs e) =>
+        WindowState = WindowState.Minimized;
+
+    /// <summary>Toggles maximize/restore. Bound to the maximize button + double-click on the drag region.</summary>
+    private void OnMaximizeRestore(object sender, RoutedEventArgs e) =>
+        WindowState = WindowState == WindowState.Maximized ? WindowState.Normal : WindowState.Maximized;
+
+    /// <summary>Custom close button.</summary>
+    private void OnClose(object sender, RoutedEventArgs e) => Close();
+
+    /// <summary>
+    /// Swap the maximize-button glyph between the "single rectangle" (when normal) and the
+    /// "two-overlapping-rectangles" (when maximized) variants, matching the Windows 11
+    /// caption-button conventions.
+    /// </summary>
+    private void OnWindowStateChanged(object? sender, EventArgs e)
+    {
+        if (FindName("MaximizeIcon") is not Path icon) return;
+        icon.Data = WindowState == WindowState.Maximized
+            // Two-rectangle "restore" glyph
+            ? System.Windows.Media.Geometry.Parse("M 2,0 L 10,0 L 10,8 M 0,2 L 8,2 L 8,10 L 0,10 Z")
+            // Single-rectangle "maximize" glyph
+            : System.Windows.Media.Geometry.Parse("M 0,0 L 10,0 L 10,10 L 0,10 Z");
+    }
 }

src/TeamsISO.App/Themes/WildDragonTheme.xaml

@@ -186,6 +186,58 @@
         </Setter>
     </Style>
 
+    <!--
+        Window-caption buttons: minimize / maximize / close. Match the Windows 11
+        Teams look — slim 46x32, hover-tinted, Close turns red on hover.
+    -->
+    <Style x:Key="Wd.Button.Caption" TargetType="Button">
+        <Setter Property="Background" Value="Transparent"/>
+        <Setter Property="BorderThickness" Value="0"/>
+        <Setter Property="Width" Value="46"/>
+        <Setter Property="Height" Value="32"/>
+        <Setter Property="Cursor" Value="Hand"/>
+        <Setter Property="FocusVisualStyle" Value="{x:Null}"/>
+        <Setter Property="HorizontalContentAlignment" Value="Center"/>
+        <Setter Property="VerticalContentAlignment" Value="Center"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="Button">
+                    <Border x:Name="Bd" Background="{TemplateBinding Background}">
+                        <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
+                    </Border>
+                    <ControlTemplate.Triggers>
+                        <Trigger Property="IsMouseOver" Value="True">
+                            <Setter TargetName="Bd" Property="Background" Value="{StaticResource Wd.SurfaceHover}"/>
+                        </Trigger>
+                        <Trigger Property="IsPressed" Value="True">
+                            <Setter TargetName="Bd" Property="Background" Value="{StaticResource Wd.SurfaceActive}"/>
+                        </Trigger>
+                    </ControlTemplate.Triggers>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <Style x:Key="Wd.Button.CaptionClose" TargetType="Button" BasedOn="{StaticResource Wd.Button.Caption}">
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="Button">
+                    <Border x:Name="Bd" Background="{TemplateBinding Background}">
+                        <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
+                    </Border>
+                    <ControlTemplate.Triggers>
+                        <Trigger Property="IsMouseOver" Value="True">
+                            <Setter TargetName="Bd" Property="Background" Value="#C42B1C"/>
+                        </Trigger>
+                        <Trigger Property="IsPressed" Value="True">
+                            <Setter TargetName="Bd" Property="Background" Value="#A52A1F"/>
+                        </Trigger>
+                    </ControlTemplate.Triggers>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
     <!-- Rail-icon button: square 48x48, used on the Teams-style left rail -->
     <Style x:Key="Wd.Button.RailIcon" TargetType="Button">
         <Setter Property="Background" Value="Transparent"/>

src/TeamsISO.App/ViewModels/ParticipantViewModel.cs

@@ -41,13 +41,13 @@ public sealed class ParticipantViewModel : ObservableObject
     private string _incomingResolution = "—";
 
     /// <summary>Number of frames the receiver has captured so far.</summary>
-    public long FramesIn { get => _framesIn; private set => SetField(ref _framesIn, value); }
+    public long FramesIn { get => _framesIn; set => SetField(ref _framesIn, value); }
 
     /// <summary>Number of frames the sender has emitted so far.</summary>
-    public long FramesOut { get => _framesOut; private set => SetField(ref _framesOut, value); }
+    public long FramesOut { get => _framesOut; set => SetField(ref _framesOut, value); }
 
     /// <summary>Source resolution as "WxH", or em-dash when no frames have been seen yet.</summary>
-    public string IncomingResolution { get => _incomingResolution; private set => SetField(ref _incomingResolution, value); }
+    public string IncomingResolution { get => _incomingResolution; set => SetField(ref _incomingResolution, value); }
 
     /// <summary>Updates the live stats display from a controller-side snapshot.</summary>
     public void UpdateStats(IsoHealthStats stats)