design: app settings + dialogs to tokens (surface 5 of the sweep)

OverlayHost (the App Settings surface) and every dialog — Go Live, Socials, Mic picker, Camera
picker, Hotkey config, Reuse Image, Rename Recording, Keep Broadcast — now resolve from tokens.
That closes the last place the creator sees a dialog: the settings overlay was still wearing the
old palette while the main window had moved on.

Every #e94560 in these files was an ERROR or validation affordance (hotkey conflicts, socials
validation, the remove tooltip, the go-live error line) — six sites all borrowing the retired
brand red to mean "something is wrong". They are `error` now, which is what the standard says
red-adjacent means; live/record keeps `primary`.

Guard list extended to all nine files.

CameraPickerDialog.xaml

@@ -1,10 +1,10 @@
-<Window x:Class="ytLive.CameraPickerDialog"
+<Window x:Class="ytLive.CameraPickerDialog"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         Title="Add Webcam" Height="340" Width="460"
         Icon="/Assets/llamacasty-icon.png"
         WindowStartupLocation="CenterOwner" ResizeMode="NoResize"
-        ShowInTaskbar="False" Background="#1a1a2e">
+        ShowInTaskbar="False" Background="{StaticResource Brush.Background}">
 
     <Window.Resources>
         <ResourceDictionary>
@@ -21,10 +21,10 @@
                             </Border>
                             <ControlTemplate.Triggers>
                                 <Trigger Property="IsMouseOver" Value="True">
-                                    <Setter TargetName="Bd" Property="Background" Value="#1c2a52"/>
+                                    <Setter TargetName="Bd" Property="Background" Value="{StaticResource Brush.SurfaceContainerHigh}"/>
                                 </Trigger>
                                 <Trigger Property="IsSelected" Value="True">
-                                    <Setter TargetName="Bd" Property="Background" Value="#2a2450"/>
+                                    <Setter TargetName="Bd" Property="Background" Value="{StaticResource Brush.SurfaceContainerHigh}"/>
                                 </Trigger>
                             </ControlTemplate.Triggers>
                         </ControlTemplate>
@@ -43,10 +43,10 @@
         </Grid.RowDefinitions>
 
         <TextBlock Grid.Row="0" Text="Add Webcam" FontSize="18" FontWeight="Bold"
-                   Foreground="#e0e0e0" Margin="0,0,0,14"/>
+                   Foreground="{StaticResource Brush.OnSurface}" Margin="0,0,0,14"/>
 
         <TextBlock Grid.Row="1" Text="Pick the camera to add to your stream."
-                   Foreground="#a0a0b0" FontSize="13" TextWrapping="Wrap" Margin="0,0,0,12"/>
+                   Foreground="{StaticResource Brush.OnSurfaceVariant}" FontSize="13" TextWrapping="Wrap" Margin="0,0,0,12"/>
 
         <Grid Grid.Row="2">
             <ListBox Background="Transparent" BorderThickness="0"
@@ -58,7 +58,7 @@
                     <DataTemplate>
                         <StackPanel Orientation="Horizontal">
                             <TextBlock Text="📷" FontSize="15" VerticalAlignment="Center" Margin="0,0,10,0"/>
-                            <TextBlock Text="{Binding Name}" Foreground="#e0e0e0" FontSize="13"
+                            <TextBlock Text="{Binding Name}" Foreground="{StaticResource Brush.OnSurface}" FontSize="13"
                                        VerticalAlignment="Center" TextTrimming="CharacterEllipsis"/>
                         </StackPanel>
                     </DataTemplate>
@@ -67,15 +67,15 @@
 
             <StackPanel VerticalAlignment="Center" HorizontalAlignment="Center"
                         Visibility="{Binding IsLoading, Converter={StaticResource BoolToVis}}">
-                <TextBlock Text="Searching for cameras…" Foreground="#a0a0b0" FontSize="13"/>
+                <TextBlock Text="Searching for cameras…" Foreground="{StaticResource Brush.OnSurfaceVariant}" FontSize="13"/>
             </StackPanel>
 
             <StackPanel VerticalAlignment="Center"
                         Visibility="{Binding NoCameras, Converter={StaticResource BoolToVis}}">
-                <TextBlock Text="No cameras found" Foreground="#e0e0e0" FontSize="15"
+                <TextBlock Text="No cameras found" Foreground="{StaticResource Brush.OnSurface}" FontSize="15"
                            FontWeight="SemiBold" HorizontalAlignment="Center"/>
                 <TextBlock Text="Check that a webcam is connected and that Windows camera access is enabled."
-                           Foreground="#a0a0b0" FontSize="13" TextWrapping="Wrap" MaxWidth="360"
+                           Foreground="{StaticResource Brush.OnSurfaceVariant}" FontSize="13" TextWrapping="Wrap" MaxWidth="360"
                            TextAlignment="Center" HorizontalAlignment="Center" Margin="0,8,0,0"/>
             </StackPanel>
         </Grid>