feat(ui): list reordering, quick actions, and resizable modals

- Drag-to-reorder user lists in the sidebar, persisted via a new
  list sort_order column (AddListSortOrder migration, backfilled by
  creation time) and ListRepository.ReorderAsync
- "Open in Explorer" / "Open in Terminal" context-menu actions on lists
- "Clear all completed" button on the Tasks island
- Inline-edit subtask titles (empty text deletes the step) and
  click-to-copy task ID in the Details island
- Make modal and planning windows resizable (BorderOnly decorations
  with min sizes) instead of fixed-size borderless

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/ClaudeDo.Ui/Views/Islands/DetailsIslandView.axaml

@@ -50,7 +50,10 @@
         <StackPanel Grid.Column="1" Spacing="0">
           <TextBlock Classes="meta"
                      Text="{Binding TaskIdBadge}"
-                     Margin="0,0,0,4"/>
+                     Margin="0,0,0,4"
+                     Cursor="Hand"
+                     ToolTip.Tip="Copy task ID"
+                     Tapped="OnTaskIdTapped"/>
           <TextBox Text="{Binding EditableTitle, Mode=TwoWay}"
                    FontSize="{StaticResource FontSizeTaskTitle}" FontWeight="Medium"
                    BorderThickness="0" Background="Transparent"
@@ -186,13 +189,30 @@
                                  Width="16" Height="16"
                                  Cursor="Hand"/>
                       </Button>
-                      <TextBlock Grid.Column="1"
-                                 Classes="subtask-title"
-                                 Text="{Binding Title}"
+                      <Panel Grid.Column="1" VerticalAlignment="Center">
+                        <TextBlock Classes="subtask-title"
+                                   Text="{Binding Title}"
+                                   IsVisible="{Binding !IsEditing}"
+                                   FontSize="{StaticResource FontSizeBody}"
+                                   Foreground="{DynamicResource TextDimBrush}"
+                                   VerticalAlignment="Center"
+                                   TextWrapping="Wrap"
+                                   Cursor="Ibeam"
+                                   Tapped="OnSubtaskTitleTapped"/>
+                        <TextBox Classes="subtask-edit"
+                                 Text="{Binding Title, Mode=TwoWay}"
+                                 IsVisible="{Binding IsEditing}"
                                  FontSize="{StaticResource FontSizeBody}"
-                                 Foreground="{DynamicResource TextDimBrush}"
-                                 VerticalAlignment="Center"
-                                 TextWrapping="Wrap"/>
+                                 AcceptsReturn="False"
+                                 TextWrapping="Wrap"
+                                 LostFocus="OnSubtaskEditLostFocus">
+                          <TextBox.KeyBindings>
+                            <KeyBinding Gesture="Enter"
+                                        Command="{Binding $parent[ItemsControl].((vm:DetailsIslandViewModel)DataContext).CommitSubtaskEditCommand}"
+                                        CommandParameter="{Binding}"/>
+                          </TextBox.KeyBindings>
+                        </TextBox>
+                      </Panel>
                     </Grid>
                   </Border>
                 </DataTemplate>

src/ClaudeDo.Ui/Views/Islands/DetailsIslandView.axaml.cs

@@ -1,9 +1,13 @@
+using System.Linq;
 using Avalonia;
 using Avalonia.Controls;
+using Avalonia.Input;
 using Avalonia.Input.Platform;
 using Avalonia.Interactivity;
 using Avalonia.Layout;
 using Avalonia.Media;
+using Avalonia.Threading;
+using Avalonia.VisualTree;
 using ClaudeDo.Ui.ViewModels.Islands;
 using ClaudeDo.Ui.Views.Modals;
 using ClaudeDo.Ui.Views.Planning;
@@ -135,6 +139,31 @@ public partial class DetailsIslandView : UserControl
         return await tcs.Task;
     }
 
+    private void OnSubtaskTitleTapped(object? sender, TappedEventArgs e)
+    {
+        if (sender is not Control c || c.DataContext is not SubtaskRowViewModel row) return;
+        row.IsEditing = true;
+
+        var box = (c.GetVisualParent() as Panel)?.GetVisualDescendants().OfType<TextBox>().FirstOrDefault();
+        if (box is not null)
+            Dispatcher.UIThread.Post(() => { box.Focus(); box.SelectAll(); }, DispatcherPriority.Background);
+    }
+
+    private void OnSubtaskEditLostFocus(object? sender, RoutedEventArgs e)
+    {
+        if (DataContext is DetailsIslandViewModel vm
+            && sender is Control c && c.DataContext is SubtaskRowViewModel row)
+            vm.CommitSubtaskEditCommand.Execute(row);
+    }
+
+    private async void OnTaskIdTapped(object? sender, TappedEventArgs e)
+    {
+        if (DataContext is not DetailsIslandViewModel vm || vm.Task is null) return;
+        var clipboard = TopLevel.GetTopLevel(this)?.Clipboard;
+        if (clipboard is null) return;
+        await clipboard.SetTextAsync(vm.Task.Id);
+    }
+
     private async void OnCopyDescriptionClick(object? sender, RoutedEventArgs e)
     {
         if (DataContext is not DetailsIslandViewModel vm) return;

src/ClaudeDo.Ui/Views/Islands/ListsIslandView.axaml

@@ -113,8 +113,18 @@
         <ItemsControl ItemsSource="{Binding UserLists}">
           <ItemsControl.ItemTemplate>
             <DataTemplate DataType="vm:ListNavItemViewModel">
-              <Border Classes="list-item" Classes.active="{Binding IsActive}"
-                      Tapped="OnItemTapped">
+              <Grid RowDefinitions="Auto,Auto,Auto">
+
+                <!-- Above-row drop indicator -->
+                <Border Grid.Row="0" Height="2" VerticalAlignment="Center" Margin="4,0"
+                        Background="{DynamicResource MossBrush}" CornerRadius="1"
+                        IsVisible="{Binding DropHintAbove}"/>
+
+              <Border Grid.Row="1" Classes="list-item" Classes.active="{Binding IsActive}"
+                      Tapped="OnItemTapped"
+                      DragDrop.AllowDrop="True"
+                      DragDrop.DragOver="OnListDragOver"
+                      DragDrop.Drop="OnListDrop">
                 <Border.ContextMenu>
                   <ContextMenu>
                     <MenuItem Header="Settings..."
@@ -123,6 +133,15 @@
                     <MenuItem Header="Worktrees…"
                               Command="{Binding $parent[UserControl].((vm:ListsIslandViewModel)DataContext).OpenWorktreesOverviewCommand}"
                               CommandParameter="{Binding}"/>
+                    <Separator IsVisible="{Binding WorkingDir, Converter={x:Static StringConverters.IsNotNullOrEmpty}}"/>
+                    <MenuItem Header="Open in Explorer"
+                              IsVisible="{Binding WorkingDir, Converter={x:Static StringConverters.IsNotNullOrEmpty}}"
+                              Command="{Binding $parent[UserControl].((vm:ListsIslandViewModel)DataContext).OpenInExplorerCommand}"
+                              CommandParameter="{Binding}"/>
+                    <MenuItem Header="Open in Terminal"
+                              IsVisible="{Binding WorkingDir, Converter={x:Static StringConverters.IsNotNullOrEmpty}}"
+                              Command="{Binding $parent[UserControl].((vm:ListsIslandViewModel)DataContext).OpenInTerminalCommand}"
+                              CommandParameter="{Binding}"/>
                   </ContextMenu>
                 </Border.ContextMenu>
                 <Grid ColumnDefinitions="20,*,Auto">
@@ -152,6 +171,12 @@
                              Text="{Binding Count}"/>
                 </Grid>
               </Border>
+
+                <!-- Below-row drop indicator (last item only) -->
+                <Border Grid.Row="2" Height="2" VerticalAlignment="Center" Margin="4,0"
+                        Background="{DynamicResource MossBrush}" CornerRadius="1"
+                        IsVisible="{Binding DropHintBelow}"/>
+              </Grid>
             </DataTemplate>
           </ItemsControl.ItemTemplate>
         </ItemsControl>

src/ClaudeDo.Ui/Views/Islands/ListsIslandView.axaml.cs

@@ -1,9 +1,11 @@
 using System.Linq;
 using Avalonia;
 using Avalonia.Controls;
+using Avalonia.Input;
 using Avalonia.Interactivity;
 using Avalonia.Layout;
 using Avalonia.Media;
+using Avalonia.VisualTree;
 using ClaudeDo.Ui.ViewModels;
 using ClaudeDo.Ui.ViewModels.Islands;
 using ClaudeDo.Ui.ViewModels.Modals;
@@ -13,9 +15,13 @@ namespace ClaudeDo.Ui.Views.Islands;
 
 public partial class ListsIslandView : UserControl
 {
+    private static readonly DataFormat<string> ListRowFormat =
+        DataFormat.CreateStringApplicationFormat("claudedo-list-row");
+
     public ListsIslandView()
     {
         InitializeComponent();
+        AddHandler(PointerPressedEvent, OnTunnelPointerPressed, RoutingStrategies.Tunnel);
         DataContextChanged += (_, _) =>
         {
             if (DataContext is ListsIslandViewModel vm)
@@ -84,6 +90,127 @@ public partial class ListsIslandView : UserControl
             vm.SelectCommand.Execute(item);
     }
 
+    private async void OnTunnelPointerPressed(object? sender, PointerPressedEventArgs e)
+    {
+        if (DataContext is not ListsIslandViewModel vm) return;
+        if (e.Source is not Visual src) return;
+
+        var border = FindListItemBorder(src);
+        if (border?.DataContext is not ListNavItemViewModel row || row.Kind != ListKind.User) return;
+        if (!e.GetCurrentPoint(border).Properties.IsLeftButtonPressed) return;
+
+        // Double-click opens the list's settings instead of starting a drag. Handled here
+        // because DoDragDropAsync captures the pointer and would swallow a DoubleTapped event.
+        if (e.ClickCount == 2)
+        {
+            vm.OpenListSettingsCommand.Execute(row);
+            return;
+        }
+
+        // Select now so the right pane updates whether the gesture becomes a click or a drag
+        // (the Tapped handler doesn't fire once DoDragDropAsync captures the pointer).
+        vm.SelectCommand.Execute(row);
+
+        var data = new DataTransfer();
+        data.Add(DataTransferItem.Create(ListRowFormat, row.Id));
+        try
+        {
+            await DragDrop.DoDragDropAsync(e, data, DragDropEffects.Move);
+        }
+        finally
+        {
+            vm.ClearDropHints();
+        }
+    }
+
+    private void OnListDragOver(object? sender, DragEventArgs e)
+    {
+        if (DataContext is not ListsIslandViewModel vm) { e.DragEffects = DragDropEffects.None; return; }
+        if (!e.DataTransfer?.Contains(ListRowFormat) ?? true)
+        {
+            e.DragEffects = DragDropEffects.None;
+            vm.ClearDropHints();
+            return;
+        }
+        if (sender is not Border b || b.DataContext is not ListNavItemViewModel target || target.Kind != ListKind.User)
+        {
+            e.DragEffects = DragDropEffects.None;
+            vm.ClearDropHints();
+            return;
+        }
+
+        var sourceId = e.DataTransfer?.TryGetValue(ListRowFormat);
+        if (string.IsNullOrEmpty(sourceId) || sourceId == target.Id)
+        {
+            e.DragEffects = DragDropEffects.None;
+            vm.ClearDropHints();
+            return;
+        }
+
+        var placeBelow = e.GetPosition(b).Y > b.Bounds.Height / 2;
+
+        // Canonicalize: "drop below X" == "drop above X+1". Only the last row shows a below-line.
+        ListNavItemViewModel hintRow = target;
+        bool hintBelow = false;
+        if (placeBelow)
+        {
+            var next = FindNextUserList(vm, target);
+            if (next is not null) { hintRow = next; hintBelow = false; }
+            else { hintRow = target; hintBelow = true; }
+        }
+
+        if (hintRow.Id == sourceId)
+        {
+            e.DragEffects = DragDropEffects.None;
+            vm.ClearDropHints();
+            return;
+        }
+
+        vm.SetDropHint(hintRow, hintBelow);
+        e.DragEffects = DragDropEffects.Move;
+    }
+
+    private async void OnListDrop(object? sender, DragEventArgs e)
+    {
+        if (DataContext is not ListsIslandViewModel vm) return;
+        try
+        {
+            if (sender is not Border b || b.DataContext is not ListNavItemViewModel target || target.Kind != ListKind.User) return;
+
+            var sourceId = e.DataTransfer?.TryGetValue(ListRowFormat);
+            if (string.IsNullOrEmpty(sourceId) || sourceId == target.Id) return;
+
+            var source = vm.UserLists.FirstOrDefault(r => r.Id == sourceId);
+            if (source is null) return;
+
+            var placeBelow = e.GetPosition(b).Y > b.Bounds.Height / 2;
+            vm.ClearDropHints();
+            await vm.ReorderAsync(source, target, placeBelow);
+        }
+        catch
+        {
+            vm.ClearDropHints();
+            throw;
+        }
+    }
+
+    private static Border? FindListItemBorder(Visual? v)
+    {
+        while (v is not null)
+        {
+            if (v is Border b && b.Classes.Contains("list-item")) return b;
+            v = v.GetVisualParent();
+        }
+        return null;
+    }
+
+    private static ListNavItemViewModel? FindNextUserList(ListsIslandViewModel vm, ListNavItemViewModel row)
+    {
+        var idx = vm.UserLists.IndexOf(row);
+        if (idx < 0) return null;
+        return idx + 1 < vm.UserLists.Count ? vm.UserLists[idx + 1] : null;
+    }
+
     private async System.Threading.Tasks.Task ShowSettingsAsync(SettingsModalViewModel settingsVm)
     {
         var owner = TopLevel.GetTopLevel(this) as Window;

src/ClaudeDo.Ui/Views/Islands/TasksIslandView.axaml

@@ -126,8 +126,17 @@
               <Binding Path="IsShowingCompleted"/>
             </MultiBinding>
           </StackPanel.IsVisible>
-          <TextBlock Classes="eyebrow section-label"
-                     Text="{Binding CompletedHeader}" Margin="14,14,14,6"/>
+          <Grid ColumnDefinitions="*,Auto" Margin="14,14,14,6">
+            <TextBlock Grid.Column="0" Classes="eyebrow section-label"
+                       Text="{Binding CompletedHeader}" VerticalAlignment="Center"/>
+            <Button Grid.Column="1" Classes="icon-btn"
+                    Command="{Binding ClearCompletedCommand}"
+                    ToolTip.Tip="Clear all completed"
+                    VerticalAlignment="Center">
+              <PathIcon Data="{StaticResource Icon.Trash}" Width="13" Height="13"
+                        Foreground="{DynamicResource BloodBrush}"/>
+            </Button>
+          </Grid>
           <ItemsControl ItemsSource="{Binding CompletedItems}">
             <ItemsControl.ItemTemplate>
               <DataTemplate DataType="vm:TaskRowViewModel">