feat(ui): add update banner and Help menu to MainWindow

src/ClaudeDo.Ui/Views/MainWindow.axaml

@@ -17,7 +17,7 @@
     <KeyBinding Gesture="Shift+OemQuestion" Command="{Binding FocusSearchCommand}"/>
     <KeyBinding Gesture="Ctrl+N" Command="{Binding FocusAddTaskCommand}"/>
   </Window.KeyBindings>
-  <Grid RowDefinitions="36,*,22">
+  <Grid RowDefinitions="36,Auto,*,22">
     <!-- Custom title bar -->
     <Border Grid.Row="0"
             Background="{DynamicResource DeepBrush}"
@@ -54,6 +54,17 @@
                      Foreground="{DynamicResource TextDimBrush}"
                      LetterSpacing="1.4"
                      VerticalAlignment="Center"/>
+          <!-- Help menu -->
+          <Menu Margin="12,0,0,0"
+                Background="Transparent"
+                VerticalAlignment="Center">
+            <MenuItem Header="Help"
+                      FontSize="11"
+                      Foreground="{DynamicResource TextDimBrush}">
+              <MenuItem Header="Check for updates"
+                        Command="{Binding CheckForUpdatesCommand}"/>
+            </MenuItem>
+          </Menu>
         </StackPanel>
 
         <!-- Middle: draggable strip -->
@@ -77,8 +88,47 @@
       </Grid>
     </Border>
 
+    <!-- Update banner -->
+    <Border Grid.Row="1"
+            Background="{DynamicResource DeepBrush}"
+            BorderBrush="{DynamicResource LineBrush}"
+            BorderThickness="0,0,0,1"
+            Padding="14,6"
+            IsVisible="{Binding IsUpdateBannerVisible}">
+      <Grid ColumnDefinitions="*,Auto,Auto">
+        <TextBlock Grid.Column="0"
+                   VerticalAlignment="Center"
+                   Foreground="{DynamicResource TextDimBrush}"
+                   FontSize="12">
+          <Run Text="Update available: v"/>
+          <Run Text="{Binding UpdateCheck.CurrentVersion}"/>
+          <Run Text=" → v"/>
+          <Run Text="{Binding UpdateBannerLatestVersion}"/>
+        </TextBlock>
+        <Button Grid.Column="1"
+                Margin="0,0,8,0"
+                Padding="10,3"
+                Content="Update now"
+                Command="{Binding UpdateNowCommand}"/>
+        <Button Grid.Column="2"
+                Padding="10,3"
+                Content="Dismiss"
+                Command="{Binding DismissBannerCommand}"/>
+      </Grid>
+    </Border>
+
+    <!-- Inline update status (appears at right of banner row when no banner) -->
+    <TextBlock Grid.Row="1"
+               HorizontalAlignment="Right"
+               VerticalAlignment="Center"
+               Margin="0,0,14,0"
+               FontSize="11"
+               Foreground="{DynamicResource TextFaintBrush}"
+               Text="{Binding InlineUpdateStatus}"
+               IsVisible="{Binding InlineUpdateStatus, Converter={x:Static ObjectConverters.IsNotNull}}"/>
+
     <!-- Background gradient layer -->
-    <Border Grid.Row="1">
+    <Border Grid.Row="2">
       <Border.Background>
         <RadialGradientBrush Center="50%,50%" GradientOrigin="50%,50%" RadiusX="70%" RadiusY="70%">
           <GradientStop Offset="0"   Color="{StaticResource DeepColor}" />
@@ -88,7 +138,7 @@
     </Border>
 
     <!-- Three islands -->
-    <Grid Grid.Row="1" Margin="7" ColumnDefinitions="260,*,320">
+    <Grid Grid.Row="2" Margin="7" ColumnDefinitions="260,*,320">
       <Border Grid.Column="0" Classes="island" Margin="7">
         <islands:ListsIslandView DataContext="{Binding Lists}"/>
       </Border>
@@ -102,7 +152,7 @@
     </Grid>
 
     <!-- Footer: connection status -->
-    <Border Grid.Row="2"
+    <Border Grid.Row="3"
             Background="{DynamicResource DeepBrush}"
             BorderBrush="{DynamicResource LineBrush}"
             BorderThickness="0,1,0,0">