fix(ui): manual modal dragging, maximize/restore icon, day-toggle style

- Drive modal title-bar dragging manually via pointer capture + Window.Position;
  Avalonia 12's BeginMoveDrag and VisualRoot-as-Window cast no longer work
  (VisualRoot is a TopLevelHost). Applies to ModalShell and WorktreeModalView.
- Toggle the MainWindow maximize button between maximize/restore glyphs on
  WindowState changes (adds Icon.WinRestore geometry).
- Add the ToggleButton.day-toggle style used by the Prime weekday picker row.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/ClaudeDo.Ui/Design/IslandStyles.axaml

@@ -21,6 +21,7 @@
     <!-- Window control icons — filled geometries (PathIcon fills, not strokes) -->
     <StreamGeometry x:Key="Icon.WinMin">M4 9 H16 V11 H4 Z</StreamGeometry>
     <StreamGeometry x:Key="Icon.WinMax">M4 4 H16 V6 H4 Z M4 14 H16 V16 H4 Z M4 4 H6 V16 H4 Z M14 4 H16 V16 H14 Z</StreamGeometry>
+    <StreamGeometry x:Key="Icon.WinRestore">M4 7 H13 V9 H4 Z M4 14 H13 V16 H4 Z M4 7 H6 V16 H4 Z M11 7 H13 V16 H11 Z M7 4 H16 V6 H7 Z M14 4 H16 V13 H14 Z</StreamGeometry>
     <StreamGeometry x:Key="Icon.WinClose">M4 5 L5 4 L16 15 L15 16 Z M15 4 L16 5 L5 16 L4 15 Z</StreamGeometry>
     <!-- Brand check glyph — filled rounded square with inset tick -->
     <StreamGeometry x:Key="Icon.BrandCheck">M3 3 H21 V21 H3 Z M6 12 L7 11 L10 14 L17 7 L18 8 L10 16 Z</StreamGeometry>
@@ -1034,4 +1035,23 @@
     <Setter Property="FontWeight"      Value="SemiBold" />
   </Style>
 
+  <!-- ============================================================ -->
+  <!-- DAY TOGGLE                                                    -->
+  <!-- Small ToggleButton for weekday pickers (Prime schedule row)  -->
+  <!-- ============================================================ -->
+  <Style Selector="ToggleButton.day-toggle">
+    <Setter Property="MinWidth" Value="34"/>
+    <Setter Property="Padding" Value="6,4"/>
+    <Setter Property="Margin" Value="0"/>
+    <Setter Property="HorizontalContentAlignment" Value="Center"/>
+    <Setter Property="Background" Value="{DynamicResource DeepBrush}"/>
+    <Setter Property="Foreground" Value="{DynamicResource TextBrush}"/>
+    <Setter Property="BorderBrush" Value="{DynamicResource LineBrush}"/>
+    <Setter Property="BorderThickness" Value="1"/>
+    <Setter Property="CornerRadius" Value="4"/>
+  </Style>
+  <Style Selector="ToggleButton.day-toggle:checked /template/ ContentPresenter">
+    <Setter Property="Background" Value="{DynamicResource AccentBrush}"/>
+  </Style>
+
 </Styles>

src/ClaudeDo.Ui/Views/Controls/ModalShell.axaml.cs

@@ -1,4 +1,3 @@
-using System;
 using System.Windows.Input;
 using Avalonia;
 using Avalonia.Controls;
@@ -23,16 +22,49 @@ public class ModalShell : ContentControl
     public object? Footer { get => GetValue(FooterProperty); set => SetValue(FooterProperty, value); }
     public ICommand? CloseCommand { get => GetValue(CloseCommandProperty); set => SetValue(CloseCommandProperty, value); }
 
+    private Window? _window;
+    private PixelPoint _dragStartScreen;
+    private PixelPoint _dragStartPos;
+    private bool _dragging;
+
     protected override void OnApplyTemplate(TemplateAppliedEventArgs e)
     {
         base.OnApplyTemplate(e);
         if (e.NameScope.Find<Border>("PART_TitleBar") is { } bar)
+        {
             bar.PointerPressed += OnTitleBarPressed;
+            bar.PointerMoved += OnTitleBarMoved;
+            bar.PointerReleased += OnTitleBarReleased;
+        }
     }
 
+    // VisualRoot is a TopLevelHost (not the Window) in Avalonia 12, so resolve the
+    // owning Window via TopLevel.GetTopLevel and drive the move manually — BeginMoveDrag
+    // and a VisualRoot-as-Window cast both fail here.
     private void OnTitleBarPressed(object? sender, PointerPressedEventArgs e)
     {
-        if (e.GetCurrentPoint(this).Properties.IsLeftButtonPressed && VisualRoot is Window w)
-            w.BeginMoveDrag(e);
+        if (!e.GetCurrentPoint(this).Properties.IsLeftButtonPressed) return;
+        _window = TopLevel.GetTopLevel(this) as Window;
+        if (_window is null) return;
+        _dragStartScreen = _window.PointToScreen(e.GetPosition(_window));
+        _dragStartPos = _window.Position;
+        _dragging = true;
+        e.Pointer.Capture(sender as IInputElement);
+    }
+
+    private void OnTitleBarMoved(object? sender, PointerEventArgs e)
+    {
+        if (!_dragging || _window is null
+            || !e.GetCurrentPoint(this).Properties.IsLeftButtonPressed) return;
+        var cur = _window.PointToScreen(e.GetPosition(_window));
+        _window.Position = new PixelPoint(
+            _dragStartPos.X + (cur.X - _dragStartScreen.X),
+            _dragStartPos.Y + (cur.Y - _dragStartScreen.Y));
+    }
+
+    private void OnTitleBarReleased(object? sender, PointerReleasedEventArgs e)
+    {
+        _dragging = false;
+        e.Pointer.Capture(null);
     }
 }

src/ClaudeDo.Ui/Views/MainWindow.axaml

@@ -82,7 +82,7 @@
             <PathIcon Data="{StaticResource Icon.WinMin}" Width="10" Height="10"/>
           </Button>
           <Button Classes="title-ctrl" Click="OnToggleMax">
-            <PathIcon Data="{StaticResource Icon.WinMax}" Width="10" Height="10"/>
+            <PathIcon x:Name="MaxIcon" Data="{StaticResource Icon.WinMax}" Width="10" Height="10"/>
           </Button>
           <Button Classes="title-ctrl close" Click="OnClose">
             <PathIcon Data="{StaticResource Icon.WinClose}" Width="10" Height="10"/>

src/ClaudeDo.Ui/Views/MainWindow.axaml.cs

@@ -19,6 +19,21 @@ public partial class MainWindow : Window
         InitializeComponent();
         KeyDown += OnWindowKeyDown;
         DataContextChanged += OnDataContextChanged;
+        UpdateMaxIcon();
+    }
+
+    protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs change)
+    {
+        base.OnPropertyChanged(change);
+        if (change.Property == WindowStateProperty)
+            UpdateMaxIcon();
+    }
+
+    private void UpdateMaxIcon()
+    {
+        var key = WindowState == WindowState.Maximized ? "Icon.WinRestore" : "Icon.WinMax";
+        if (this.TryFindResource(key, out var geometry) && geometry is Geometry g)
+            MaxIcon.Data = g;
     }
 
     private void OnDataContextChanged(object? sender, EventArgs e)

src/ClaudeDo.Ui/Views/Modals/WorktreeModalView.axaml

@@ -28,7 +28,10 @@
 
       <!-- Title strip -->
       <Border DockPanel.Dock="Top" Height="36"
-              PointerPressed="OnTitleBarPressed">
+              Background="Transparent"
+              PointerPressed="OnTitleBarPressed"
+              PointerMoved="OnTitleBarMoved"
+              PointerReleased="OnTitleBarReleased">
         <Grid ColumnDefinitions="*,Auto" Margin="14,0">
           <TextBlock Grid.Column="0" Text="Worktree" VerticalAlignment="Center"
                      FontFamily="{DynamicResource MonoFont}" FontSize="{StaticResource FontSizeBody}"

src/ClaudeDo.Ui/Views/Modals/WorktreeModalView.axaml.cs

@@ -66,9 +66,31 @@ public partial class WorktreeModalView : Window
         e.Handled = true;
     }
 
+    private PixelPoint _dragStartScreen;
+    private PixelPoint _dragStartPos;
+    private bool _dragging;
+
     private void OnTitleBarPressed(object? sender, PointerPressedEventArgs e)
     {
-        if (e.GetCurrentPoint(this).Properties.IsLeftButtonPressed)
-            BeginMoveDrag(e);
+        if (!e.GetCurrentPoint(this).Properties.IsLeftButtonPressed) return;
+        _dragStartScreen = this.PointToScreen(e.GetPosition(this));
+        _dragStartPos = Position;
+        _dragging = true;
+        e.Pointer.Capture(sender as IInputElement);
+    }
+
+    private void OnTitleBarMoved(object? sender, PointerEventArgs e)
+    {
+        if (!_dragging || !e.GetCurrentPoint(this).Properties.IsLeftButtonPressed) return;
+        var cur = this.PointToScreen(e.GetPosition(this));
+        Position = new PixelPoint(
+            _dragStartPos.X + (cur.X - _dragStartScreen.X),
+            _dragStartPos.Y + (cur.Y - _dragStartScreen.Y));
+    }
+
+    private void OnTitleBarReleased(object? sender, PointerReleasedEventArgs e)
+    {
+        _dragging = false;
+        e.Pointer.Capture(null);
     }
 }