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.

RenameRecordingDialog.xaml

@@ -1,10 +1,10 @@
-<Window x:Class="ytLive.RenameRecordingDialog"
+<Window x:Class="ytLive.RenameRecordingDialog"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         Title="Rename Recording" Height="304" Width="460"
         Icon="/ytLive;component/Assets/llamacasty-icon.png"
         WindowStartupLocation="CenterOwner" ResizeMode="NoResize"
-        ShowInTaskbar="False" Background="#1a1a2e">
+        ShowInTaskbar="False" Background="{StaticResource Brush.Background}">
 
     <Grid Margin="24">
         <Grid.RowDefinitions>
@@ -16,9 +16,9 @@
         </Grid.RowDefinitions>
 
         <TextBlock Grid.Row="0" Text="Rename Recording" FontSize="18" FontWeight="Bold"
-                   Foreground="#e0e0e0" Margin="0,0,0,12"/>
+                   Foreground="{StaticResource Brush.OnSurface}" Margin="0,0,0,12"/>
 
-        <TextBlock Grid.Row="1" TextWrapping="Wrap" Foreground="#a0a0b0" FontSize="13"
+        <TextBlock Grid.Row="1" TextWrapping="Wrap" Foreground="{StaticResource Brush.OnSurfaceVariant}" FontSize="13"
                    Margin="0,0,0,16">
             The recording is saved with an auto-generated name. Give it a clearer name —
             leave it empty to keep the auto name.