feat(ui): merge action and robust jump-to-task in worktrees overview

Add Merge entry to the worktrees overview context menu wiring the existing
MergeModalViewModel, replace fire-and-forget list selection with a
collection-change-aware JumpToTaskHelper, and propagate list renames to
visible task rows via a new ListUpdated event.

Harden worktree state changes: WorkerHub.SetWorktreeState now rejects
invalid transitions, WorktreeMaintenanceService only drops the DB row when
the on-disk worktree was actually removed, and Cleanup/Reset broadcast
WorktreeUpdated for affected tasks. SetWorktreeStateAsync returns the hub
error message so the modal can surface it.

Also: de-duplicate the worktrees overview modal opener, hook
OnParentTaskIdChanged to refresh IsDraft, fix MergeModal CanExecute
notifications, and add WorktreeStateHubTests for the transition rules.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

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

@@ -1,6 +1,10 @@
 using System.Linq;
+using Avalonia;
 using Avalonia.Controls;
 using Avalonia.Interactivity;
+using Avalonia.Layout;
+using Avalonia.Media;
+using ClaudeDo.Ui.ViewModels;
 using ClaudeDo.Ui.ViewModels.Islands;
 using ClaudeDo.Ui.ViewModels.Modals;
 using ClaudeDo.Ui.Views.Modals;
@@ -28,26 +32,34 @@ public partial class ListsIslandView : UserControl
                 };
                 vm.ShowWorktreesOverviewModal = async modal =>
                 {
+                    var top = TopLevel.GetTopLevel(this) as Window;
+                    var shell = top?.DataContext as IslandsShellViewModel;
                     var window = new WorktreesOverviewModalView { DataContext = modal };
                     modal.CloseAction = () => window.Close();
-                    modal.JumpToTaskAction = (listId, _) =>
+                    modal.JumpToTaskAction = (listId, taskId) =>
                     {
-                        if (vm is { } v)
-                        {
-                            var item = v.UserLists.FirstOrDefault(l => l.Id == $"user:{listId}");
-                            if (item is not null) v.SelectedList = item;
-                        }
+                        if (shell is not null)
+                            _ = JumpToTaskAsync(shell, listId, taskId);
                     };
                     modal.ShowDiffAction = diffVm =>
                     {
-                        var top2 = TopLevel.GetTopLevel(this) as Window;
-                        if (top2 is null) return;
+                        if (top is null) return;
                         var dlg = new WorktreeModalView { DataContext = diffVm };
                         diffVm.CloseAction = () => dlg.Close();
                         _ = diffVm.LoadAsync();
-                        _ = dlg.ShowDialog(top2);
+                        _ = dlg.ShowDialog(top);
                     };
-                    var top = TopLevel.GetTopLevel(this) as Window;
+                    modal.ConfirmAction = ShowConfirmAsync;
+                    if (shell is not null)
+                    {
+                        modal.ResolveMergeVm = shell.ResolveMergeVm;
+                        modal.ShowMergeAction = async mergeVm =>
+                        {
+                            if (top is null) return;
+                            var mergeDlg = new MergeModalView { DataContext = mergeVm };
+                            await mergeDlg.ShowDialog(top);
+                        };
+                    }
                     if (top is null) window.Show();
                     else await window.ShowDialog(top);
                 };
@@ -69,4 +81,51 @@ public partial class ListsIslandView : UserControl
         var modal = new SettingsModalView { DataContext = settingsVm };
         await modal.ShowDialog(owner);
     }
+
+    private static System.Threading.Tasks.Task JumpToTaskAsync(IslandsShellViewModel s, string listId, string taskId)
+        => JumpToTaskHelper.SelectAsync(s, listId, taskId);
+
+    private async System.Threading.Tasks.Task<bool> ShowConfirmAsync(string message)
+    {
+        var owner = TopLevel.GetTopLevel(this) as Window;
+        if (owner is null) return false;
+
+        var tcs = new TaskCompletionSource<bool>();
+        var cancel = new Button { Content = "Cancel", MinWidth = 90 };
+        var confirm = new Button { Content = "Confirm", MinWidth = 90, Classes = { "danger" } };
+
+        var dialog = new Window
+        {
+            Title = "Confirm",
+            Width = 380,
+            SizeToContent = SizeToContent.Height,
+            CanResize = false,
+            WindowStartupLocation = WindowStartupLocation.CenterOwner,
+            ShowInTaskbar = false,
+            Background = this.FindResource("SurfaceBrush") as IBrush,
+            Content = new StackPanel
+            {
+                Margin = new Thickness(20),
+                Spacing = 16,
+                Children =
+                {
+                    new TextBlock { Text = message, TextWrapping = TextWrapping.Wrap },
+                    new StackPanel
+                    {
+                        Orientation = Orientation.Horizontal,
+                        HorizontalAlignment = HorizontalAlignment.Right,
+                        Spacing = 8,
+                        Children = { cancel, confirm },
+                    },
+                },
+            },
+        };
+
+        cancel.Click += (_, _) => { tcs.TrySetResult(false); dialog.Close(); };
+        confirm.Click += (_, _) => { tcs.TrySetResult(true); dialog.Close(); };
+        dialog.Closed += (_, _) => tcs.TrySetResult(false);
+
+        _ = dialog.ShowDialog(owner);
+        return await tcs.Task;
+    }
 }

src/ClaudeDo.Ui/Views/JumpToTaskHelper.cs

@@ -0,0 +1,42 @@
+using System.Collections.Specialized;
+using System.Linq;
+using System.Threading.Tasks;
+using ClaudeDo.Ui.ViewModels;
+
+namespace ClaudeDo.Ui.Views;
+
+internal static class JumpToTaskHelper
+{
+    // Selects the list, then waits for the matching task row to appear in Tasks.Items.
+    // Listens to CollectionChanged so it works regardless of how long LoadForListAsync takes;
+    // bounded by a hard timeout so we never hang if the task is filtered out.
+    public static async Task SelectAsync(IslandsShellViewModel s, string listId, string taskId)
+    {
+        if (s.Lists is null || s.Tasks is null) return;
+        var item = s.Lists.UserLists.FirstOrDefault(l => l.Id == $"user:{listId}");
+        if (item is null) return;
+        s.Lists.SelectedList = item;
+
+        var existing = s.Tasks.Items.FirstOrDefault(r => r.Id == taskId);
+        if (existing is not null) { s.Tasks.SelectedTask = existing; return; }
+
+        var tcs = new TaskCompletionSource<bool>();
+        void OnChanged(object? _, NotifyCollectionChangedEventArgs __)
+        {
+            var row = s.Tasks!.Items.FirstOrDefault(r => r.Id == taskId);
+            if (row is not null) tcs.TrySetResult(true);
+        }
+
+        s.Tasks.Items.CollectionChanged += OnChanged;
+        try
+        {
+            await Task.WhenAny(tcs.Task, Task.Delay(5000));
+            var row = s.Tasks.Items.FirstOrDefault(r => r.Id == taskId);
+            if (row is not null) s.Tasks.SelectedTask = row;
+        }
+        finally
+        {
+            s.Tasks.Items.CollectionChanged -= OnChanged;
+        }
+    }
+}

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

@@ -1,6 +1,9 @@
 using System.Linq;
+using Avalonia;
 using Avalonia.Controls;
 using Avalonia.Input;
+using Avalonia.Layout;
+using Avalonia.Media;
 using ClaudeDo.Ui.ViewModels;
 using ClaudeDo.Ui.ViewModels.Islands;
 using ClaudeDo.Ui.ViewModels.Modals;
@@ -38,13 +41,10 @@ public partial class MainWindow : Window
             {
                 var dlg = new WorktreesOverviewModalView { DataContext = modal };
                 modal.CloseAction = () => dlg.Close();
-                modal.JumpToTaskAction = (listId, _) =>
+                modal.JumpToTaskAction = (listId, taskId) =>
                 {
                     if (DataContext is IslandsShellViewModel s)
-                    {
-                        var item = s.Lists?.UserLists.FirstOrDefault(l => l.Id == $"user:{listId}");
-                        if (item is not null && s.Lists is not null) s.Lists.SelectedList = item;
-                    }
+                        _ = JumpToTaskAsync(s, listId, taskId);
                 };
                 modal.ShowDiffAction = diffVm =>
                 {
@@ -53,6 +53,13 @@ public partial class MainWindow : Window
                     _ = diffVm.LoadAsync();
                     _ = diffDlg.ShowDialog(this);
                 };
+                modal.ConfirmAction = ShowConfirmAsync;
+                modal.ResolveMergeVm = vm.ResolveMergeVm;
+                modal.ShowMergeAction = async mergeVm =>
+                {
+                    var mergeDlg = new MergeModalView { DataContext = mergeVm };
+                    await mergeDlg.ShowDialog(this);
+                };
                 await dlg.ShowDialog(this);
             };
         }
@@ -85,4 +92,48 @@ public partial class MainWindow : Window
         base.OnSizeChanged(e);
         if (DataContext is IslandsShellViewModel vm) vm.WindowWidth = Bounds.Width;
     }
+
+    private static System.Threading.Tasks.Task JumpToTaskAsync(IslandsShellViewModel s, string listId, string taskId)
+        => JumpToTaskHelper.SelectAsync(s, listId, taskId);
+
+    private async System.Threading.Tasks.Task<bool> ShowConfirmAsync(string message)
+    {
+        var tcs = new TaskCompletionSource<bool>();
+        var cancel = new Button { Content = "Cancel", MinWidth = 90 };
+        var confirm = new Button { Content = "Confirm", MinWidth = 90, Classes = { "danger" } };
+
+        var dialog = new Window
+        {
+            Title = "Confirm",
+            Width = 380,
+            SizeToContent = SizeToContent.Height,
+            CanResize = false,
+            WindowStartupLocation = WindowStartupLocation.CenterOwner,
+            ShowInTaskbar = false,
+            Background = this.FindResource("SurfaceBrush") as IBrush,
+            Content = new StackPanel
+            {
+                Margin = new Thickness(20),
+                Spacing = 16,
+                Children =
+                {
+                    new TextBlock { Text = message, TextWrapping = TextWrapping.Wrap },
+                    new StackPanel
+                    {
+                        Orientation = Orientation.Horizontal,
+                        HorizontalAlignment = HorizontalAlignment.Right,
+                        Spacing = 8,
+                        Children = { cancel, confirm },
+                    },
+                },
+            },
+        };
+
+        cancel.Click += (_, _) => { tcs.TrySetResult(false); dialog.Close(); };
+        confirm.Click += (_, _) => { tcs.TrySetResult(true); dialog.Close(); };
+        dialog.Closed += (_, _) => tcs.TrySetResult(false);
+
+        _ = dialog.ShowDialog(this);
+        return await tcs.Task;
+    }
 }

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

@@ -32,6 +32,10 @@
                       Command="{Binding $parent[Window].((vm:WorktreesOverviewModalViewModel)DataContext).JumpToTaskCommand}"
                       CommandParameter="{Binding}"/>
             <Separator/>
+            <MenuItem Header="Merge…"
+                      IsEnabled="{Binding IsActive}"
+                      Command="{Binding $parent[Window].((vm:WorktreesOverviewModalViewModel)DataContext).MergeCommand}"
+                      CommandParameter="{Binding}"/>
             <MenuItem Header="Discard"
                       IsEnabled="{Binding IsActive}"
                       Command="{Binding $parent[Window].((vm:WorktreesOverviewModalViewModel)DataContext).DiscardCommand}"