feat(winui3): WinUI 3 host LAUNCHES — verified rendering on Windows

Removing the inline-hosted SettingsDrawer (and its accompanying
Storyboard resources targeting TranslateTransform.X) unblocks the
launch. The WinUI 3 host now opens, paints, and stays alive. Verified
via screenshot:

  * 64px left rail with Wild Dragon "W" brand mark + participants /
    Teams / hide-Teams / settings / engine-status puck buttons (Segoe
    Fluent Icons throughout, uniform stroke)
  * 44px custom title bar with the live pills inline (live · session
    timer · REC count · disk free) and a theme toggle to the left of
    the system min/max/close
  * Section header: "Participants 4" + filter input + Refresh +
    Presets + the single cyan Primary CTA "Enable all online"
  * Participants list placeholder ("View-model wiring queued for the
    next session") in the hero row — real DataGrid + bindings land in
    Phase 4/5 of the migration plan
  * Conditional in-call control bar: Muted (destructive coral) +
    Camera/Share/Marker (Secondary) + Leave (destructive coral) +
    overflow kebab
  * Slim status bar: control-surface URL + keyboard shortcut hints
  * Rendered in LIGHT THEME on first run (matched the OS app-mode
    setting via ThemeManager.ResolveTheme), confirming the
    ThemeDictionary swap works end-to-end

Two open suspects causing the SettingsDrawer host to crash WinUI 3's
XAML parser with HR=0x802b000a (XAML_E_PARSER_GENERAL_ERROR):

  * RenderTransform with a x:Name'd TranslateTransform — WinUI 3
    might not allow naming transforms inside RenderTransform the way
    WPF does
  * Storyboard.TargetName pointing at the named transform — WinUI 3
    Storyboards have stricter resolution

The drawer XAML itself (Views/SettingsDrawer.xaml + .cs) is unchanged
and ships alongside this commit. Re-host it in MainWindow.xaml once
the parse error is triaged (likely fix: replace TranslateTransform.X
animation with the AppWindow composition API or use the
CompositionTarget approach instead of a Storyboard).

The migration plan's Phase 3 is now substantially CLOSED — the
WindowsAppSDK activation blocker is resolved (1.8 DDLM swap). Next
session opens with Phase 4 (view-model wiring) plus the SettingsDrawer
re-host triage.

src/TeamsISO.App.WinUI/Views/MainWindow.xaml

@@ -33,29 +33,9 @@
             <ColumnDefinition Width="64"/>
             <ColumnDefinition Width="*"/>
         </Grid.ColumnDefinitions>
-        <Grid.Resources>
+        <!-- Drawer slide storyboards removed temporarily to isolate the
-            <!-- Drawer slide-in: 220ms ease-out-quart, translates 400px → 0 -->
+             XAML parse error blocking launch on WindowsAppSDK 1.8. -->
-            <Storyboard x:Key="DrawerSlideIn">
+
-                <DoubleAnimation Storyboard.TargetName="DrawerTransform"
-                                 Storyboard.TargetProperty="X"
-                                 To="0"
-                                 Duration="0:0:0.22">
-                    <DoubleAnimation.EasingFunction>
-                        <QuarticEase EasingMode="EaseOut"/>
-                    </DoubleAnimation.EasingFunction>
-                </DoubleAnimation>
-            </Storyboard>
-            <Storyboard x:Key="DrawerSlideOut">
-                <DoubleAnimation Storyboard.TargetName="DrawerTransform"
-                                 Storyboard.TargetProperty="X"
-                                 To="400"
-                                 Duration="0:0:0.18">
-                    <DoubleAnimation.EasingFunction>
-                        <QuarticEase EasingMode="EaseIn"/>
-                    </DoubleAnimation.EasingFunction>
-                </DoubleAnimation>
-            </Storyboard>
-        </Grid.Resources>
 
         <!-- ═══════════════════════ LEFT RAIL ═══════════════════════ -->
         <Border Grid.Column="0"
@@ -397,17 +377,11 @@
                 </StackPanel>
             </Border>
 
-            <!-- ─── Settings drawer (slides over rows 1-3) ─── -->
+            <!-- Settings drawer host removed temporarily to isolate the
-            <views:SettingsDrawer x:Name="SettingsDrawerHost"
+                 XAML parse error blocking launch on WindowsAppSDK 1.8.
-                                  Grid.Row="0"
+                 The drawer XAML itself is unchanged and remains in
-                                  Grid.RowSpan="4"
+                 Views/SettingsDrawer.xaml. Re-host once the parse error
-                                  HorizontalAlignment="Right"
+                 is triaged. -->
-                                  Width="400"
-                                  IsHitTestVisible="False">
-                <views:SettingsDrawer.RenderTransform>
-                    <TranslateTransform x:Name="DrawerTransform" X="400"/>
-                </views:SettingsDrawer.RenderTransform>
-            </views:SettingsDrawer>
 
             <!-- ─── Status bar ─── -->
             <Grid Grid.Row="4"

src/TeamsISO.App.WinUI/Views/MainWindow.xaml.cs

@@ -60,50 +60,16 @@ public sealed partial class MainWindow : Window
         ThemeManager.Current.Toggle();
     }
 
-    private bool _drawerOpen;
-
     /// <summary>
-    /// Toggle the settings drawer with a slide animation. The drawer is
+    /// Drawer toggle stubbed pending XAML-parse-error triage. The
-    /// pre-translated 400px off the right edge in XAML; the storyboard
+    /// SettingsDrawer XAML itself builds clean and is hosted inline once
-    /// animates X back to 0 to slide it in. Hit-testing is gated so the
+    /// the launch crash is resolved (see Phase 3 of the migration plan).
-    /// off-screen drawer doesn't intercept clicks on the participants list.
     /// </summary>
     private void OnSettingsClick(object sender, RoutedEventArgs e)
     {
-        if (_drawerOpen)
+        // No-op stub until SettingsDrawerHost re-hosts in MainWindow.xaml.
-        {
-            CloseDrawer();
-        }
-        else
-        {
-            OpenDrawer();
-        }
     }
 
-    private void OpenDrawer()
-    {
-        if (_drawerOpen) return;
-        _drawerOpen = true;
-        SettingsDrawerHost.IsHitTestVisible = true;
-        var sb = (Microsoft.UI.Xaml.Media.Animation.Storyboard)((Microsoft.UI.Xaml.Controls.Grid)Content)
-            .Resources["DrawerSlideIn"];
-        sb.Begin();
-        SettingsDrawerHost.CloseRequested -= OnDrawerCloseRequested;
-        SettingsDrawerHost.CloseRequested += OnDrawerCloseRequested;
-    }
-
-    private void CloseDrawer()
-    {
-        if (!_drawerOpen) return;
-        _drawerOpen = false;
-        var sb = (Microsoft.UI.Xaml.Media.Animation.Storyboard)((Microsoft.UI.Xaml.Controls.Grid)Content)
-            .Resources["DrawerSlideOut"];
-        sb.Completed += (_, _) => SettingsDrawerHost.IsHitTestVisible = false;
-        sb.Begin();
-    }
-
-    private void OnDrawerCloseRequested(object? sender, System.EventArgs e) => CloseDrawer();
-
     /// <summary>
     /// Push a resolved theme to the visual tree and to the AppWindow
     /// title-bar buttons. Called on every <see cref="ThemeManager.Themed"/>