feat(merge): resolve conflicts straight from the merge modal

The merge modal previews the selected target and offers 'Resolve conflicts' next to the stash retry when it predicts a conflict. A dirty target is autostashed. The resolver now aborts when closed natively (Alt+F4), so the merge and its autostash can never be left pending.

src/ClaudeDo.Localization/locales/de.json

@@ -539,7 +539,8 @@
       "removeWorktree": "Worktree nach dem Mergen entfernen",
       "commitMessage": "Commit-Nachricht",
       "conflictedFiles": "Konfliktdateien:",
-      "stashAndMerge": "Änderungen stashen und mergen"
+      "stashAndMerge": "Änderungen stashen und mergen",
+      "resolveConflicts": "Konflikte lösen"
     },
     "diff": {
       "title": "DIFF",

src/ClaudeDo.Localization/locales/en.json

@@ -539,7 +539,8 @@
       "removeWorktree": "Remove worktree after merge",
       "commitMessage": "Commit message",
       "conflictedFiles": "Conflicted files:",
-      "stashAndMerge": "Stash changes and merge"
+      "stashAndMerge": "Stash changes and merge",
+      "resolveConflicts": "Resolve conflicts"
     },
     "diff": {
       "title": "DIFF",

src/ClaudeDo.Ui/ViewModels/Conflicts/ConflictResolverViewModel.cs

@@ -122,6 +122,9 @@ public sealed partial class ConflictResolverViewModel : ObservableObject
     public string TaskId => _taskId;
     public Action? CloseRequested { get; set; }
 
+    /// <summary>True once the merge was continued or aborted; a window closed before that must abort, or the repo stays mid-merge with an autostash pending.</summary>
+    public bool IsSettled { get; private set; }
+
     /// <summary>Raised when the current conflict changes so the view can reload its editors.</summary>
     public event Action? CurrentChanged;
 
@@ -277,13 +280,17 @@ public sealed partial class ConflictResolverViewModel : ObservableObject
                 // Hand back to the orchestrator: it commits this subtask and drains the rest.
                 // A later subtask conflict re-opens this editor via the PlanningMergeConflict broadcast.
                 await _worker.ContinuePlanningMergeAsync(_planningParentId);
+                IsSettled = true;
                 CloseRequested?.Invoke();
                 return;
             }
 
             var result = await _worker.ContinueConflictMergeAsync(_taskId);
             if (string.Equals(result.Status, "merged", StringComparison.Ordinal))
+            {
+                IsSettled = true;
                 CloseRequested?.Invoke();
+            }
             else
                 Error = result.ErrorMessage ?? "Conflicts not fully resolved — review and retry.";
         }
@@ -297,6 +304,7 @@ public sealed partial class ConflictResolverViewModel : ObservableObject
     [RelayCommand]
     private async Task AbortAsync()
     {
+        IsSettled = true;
         IsBusy = true;
         try
         {

src/ClaudeDo.Ui/ViewModels/Modals/MergeModalViewModel.cs

@@ -16,11 +16,11 @@ public sealed partial class MergeModalViewModel : ViewModelBase
 
     public ObservableCollection<string> Branches { get; } = new();
 
-    [ObservableProperty][NotifyCanExecuteChangedFor(nameof(SubmitCommand))] private string? _selectedBranch;
+    [ObservableProperty][NotifyCanExecuteChangedFor(nameof(SubmitCommand), nameof(ResolveConflictsCommand))] private string? _selectedBranch;
     [ObservableProperty] private bool _removeWorktree = true;
     [ObservableProperty] private string _commitMessage = "";
 
-    [ObservableProperty][NotifyCanExecuteChangedFor(nameof(SubmitCommand))] private bool _isBusy;
+    [ObservableProperty][NotifyCanExecuteChangedFor(nameof(SubmitCommand), nameof(ResolveConflictsCommand))] private bool _isBusy;
 
     /// What the pending merge is doing right now, fed by the worker's MergeProgress broadcast.
     /// A merge whose list has a verify command can occupy this call for minutes — without this the
@@ -37,6 +37,11 @@ public sealed partial class MergeModalViewModel : ViewModelBase
     [ObservableProperty] private bool _showStashRetry;
     [ObservableProperty] private IReadOnlyList<string> _conflictFiles = Array.Empty<string>();
 
+    /// <summary>The merge preview for the selected branch predicts a conflict — offers the resolver up front.</summary>
+    [ObservableProperty] private bool _previewHasConflict;
+
+    private bool _targetDirty;
+
     public Action? CloseAction { get; set; }
 
     /// True once a merge has succeeded — lets the caller (e.g. the diff window)
@@ -79,6 +84,7 @@ public sealed partial class MergeModalViewModel : ViewModelBase
 
             // Known dirty before anyone clicks Merge — offer the stash retry right away instead
             // of making the user hit the "dirty_target" refusal first.
+            _targetDirty = targets.TargetDirty;
             if (targets.TargetDirty)
             {
                 WarningMessage = Loc.T("vm.merge.targetDirty");
@@ -92,6 +98,29 @@ public sealed partial class MergeModalViewModel : ViewModelBase
         finally { IsBusy = false; }
     }
 
+    partial void OnSelectedBranchChanged(string? value) => _ = RefreshPreviewAsync(value);
+
+    private async Task RefreshPreviewAsync(string? branch)
+    {
+        PreviewHasConflict = false;
+        if (string.IsNullOrWhiteSpace(branch) || string.IsNullOrEmpty(TaskId)) return;
+        try
+        {
+            var dto = await _worker.PreviewMergeAsync(TaskId, branch);
+            if (SelectedBranch == branch) PreviewHasConflict = dto?.ConflictFiles.Count > 0;
+        }
+        catch { /* preview is a hint only; Merge still reports the real conflict */ }
+    }
+
+    /// <summary>Hands the predicted conflict straight to the resolver; stashes a dirty target, as the warning above announces.</summary>
+    [RelayCommand(CanExecute = nameof(CanSubmit))]
+    private async Task ResolveConflictsAsync()
+    {
+        RoutedToResolver = true;
+        CloseAction?.Invoke();
+        await _merge.ResolveConflictAsync(TaskId, SelectedBranch!, _targetDirty);
+    }
+
     private bool CanSubmit() =>
         !IsBusy && !HasConflict && !string.IsNullOrWhiteSpace(SelectedBranch);
 

src/ClaudeDo.Ui/Views/Conflicts/ConflictResolverView.axaml.cs

@@ -42,6 +42,13 @@ public partial class ConflictResolverView : Window
         InitializeComponent();
     }
 
+    /// <summary>Alt+F4 bypasses the Abort-bound close button; abort here so the merge and its autostash never stay pending.</summary>
+    protected override void OnClosed(EventArgs e)
+    {
+        base.OnClosed(e);
+        if (_vm is { IsSettled: false }) _vm.AbortCommand.Execute(null);
+    }
+
     protected override void OnDataContextChanged(EventArgs e)
     {
         base.OnDataContextChanged(e);

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

@@ -74,10 +74,16 @@
                    TextWrapping="Wrap"
                    IsVisible="{Binding WarningMessage, Converter={x:Static ObjectConverters.IsNotNull}}" />
 
-        <Button Classes="btn" HorizontalAlignment="Left"
-                Content="{loc:Tr modals.merge.stashAndMerge}"
-                Command="{Binding StashAndMergeCommand}"
-                IsVisible="{Binding ShowStashRetry}" />
+        <StackPanel Orientation="Horizontal" Spacing="8">
+          <Button Classes="btn"
+                  Content="{loc:Tr modals.merge.stashAndMerge}"
+                  Command="{Binding StashAndMergeCommand}"
+                  IsVisible="{Binding ShowStashRetry}" />
+          <Button Classes="btn"
+                  Content="{loc:Tr modals.merge.resolveConflicts}"
+                  Command="{Binding ResolveConflictsCommand}"
+                  IsVisible="{Binding PreviewHasConflict}" />
+        </StackPanel>
 
         <Border Classes="danger-box"
                 IsVisible="{Binding HasConflict}">