merge(layer-c): inline conflict resolver + worker conflict plumbing

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

@@ -0,0 +1,49 @@
+using System.Collections.Generic;
+using System.Linq;
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+
+namespace ClaudeDo.Ui.ViewModels.Conflicts;
+
+public sealed partial class ConflictHunk : ObservableObject
+{
+    public string Ours { get; }
+    public string Theirs { get; }
+    public string? Base { get; }
+
+    [ObservableProperty] private string? _resolution;
+
+    public bool IsResolved => Resolution is not null;
+
+    public ConflictHunk(string ours, string theirs, string? @base)
+    {
+        Ours = ours;
+        Theirs = theirs;
+        Base = @base;
+    }
+
+    partial void OnResolutionChanged(string? value) => OnPropertyChanged(nameof(IsResolved));
+
+    [RelayCommand] private void AcceptCurrent()  => Resolution = Ours;
+    [RelayCommand] private void AcceptIncoming() => Resolution = Theirs;
+    [RelayCommand] private void AcceptBoth()     => Resolution = Ours + Theirs;
+    [RelayCommand] private void EditManually()   => Resolution ??= Ours;
+}
+
+public sealed class ConflictFile
+{
+    public string Path { get; }
+    public IReadOnlyList<ConflictHunk> Hunks { get; }
+
+    public ConflictFile(string path, IReadOnlyList<ConflictHunk> hunks)
+    {
+        Path = path;
+        Hunks = hunks;
+    }
+
+    public bool AllHunksResolved => Hunks.Count > 0 && Hunks.All(h => h.IsResolved);
+
+    /// <summary>Merged file content: concatenation of each hunk's resolution
+    /// (single whole-file hunk today; concatenation stays correct for multi-hunk later).</summary>
+    public string ComposeResolvedContent() => string.Concat(Hunks.Select(h => h.Resolution));
+}

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

@@ -0,0 +1,116 @@
+using System;
+using System.Collections.ObjectModel;
+using System.ComponentModel;
+using System.Linq;
+using System.Threading.Tasks;
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using ClaudeDo.Ui.Services;
+
+namespace ClaudeDo.Ui.ViewModels.Conflicts;
+
+public sealed partial class ConflictResolverViewModel : ObservableObject
+{
+    private readonly IWorkerClient _worker;
+    private readonly string _taskId;
+
+    public ObservableCollection<ConflictFile> Files { get; } = new();
+
+    [ObservableProperty] private bool _isBusy;
+    [ObservableProperty] private string? _error;
+    [ObservableProperty] private bool _canContinue;
+
+    public string TaskId => _taskId;
+    public Action? CloseRequested { get; set; }
+
+    public ConflictResolverViewModel(IWorkerClient worker, string taskId)
+    {
+        _worker = worker;
+        _taskId = taskId;
+    }
+
+    /// <summary>Starts the conflict merge and loads ours/theirs/base per file.
+    /// Returns true when there are conflicts to resolve (caller should show the dialog).</summary>
+    public async Task<bool> OpenAsync(string targetBranch)
+    {
+        IsBusy = true;
+        Error = null;
+        try
+        {
+            var start = await _worker.StartConflictMergeAsync(_taskId, targetBranch);
+            if (!string.Equals(start.Status, "conflict", StringComparison.Ordinal))
+            {
+                if (string.Equals(start.Status, "blocked", StringComparison.Ordinal))
+                    Error = start.ErrorMessage;
+                return false;
+            }
+
+            var conflicts = await _worker.GetMergeConflictsAsync(_taskId);
+            Files.Clear();
+            foreach (var f in conflicts.Files)
+            {
+                var hunks = f.Hunks.Select(h =>
+                {
+                    var hk = new ConflictHunk(h.Ours, h.Theirs, h.Base);
+                    hk.PropertyChanged += OnHunkChanged;
+                    return hk;
+                }).ToList();
+                Files.Add(new ConflictFile(f.Path, hunks));
+            }
+            RecomputeCanContinue();
+            return Files.Count > 0;
+        }
+        catch (Exception ex)
+        {
+            Error = ex.Message;
+            return false;
+        }
+        finally { IsBusy = false; }
+    }
+
+    private void OnHunkChanged(object? sender, PropertyChangedEventArgs e)
+    {
+        if (e.PropertyName is nameof(ConflictHunk.IsResolved) or nameof(ConflictHunk.Resolution))
+            RecomputeCanContinue();
+    }
+
+    private void RecomputeCanContinue()
+        => CanContinue = Files.Count > 0 && Files.All(f => f.AllHunksResolved);
+
+    [RelayCommand]
+    private async Task ContinueAsync()
+    {
+        if (!CanContinue) return;
+        IsBusy = true;
+        Error = null;
+        try
+        {
+            foreach (var file in Files)
+                await _worker.WriteConflictResolutionAsync(_taskId, file.Path, file.ComposeResolvedContent());
+
+            var result = await _worker.ContinueMergeAsync(_taskId);
+            if (string.Equals(result.Status, "merged", StringComparison.Ordinal))
+                CloseRequested?.Invoke();
+            else
+                Error = result.ErrorMessage ?? "Conflicts not fully resolved — review and retry.";
+        }
+        catch (Exception ex)
+        {
+            Error = ex.Message;
+        }
+        finally { IsBusy = false; }
+    }
+
+    [RelayCommand]
+    private async Task AbortAsync()
+    {
+        IsBusy = true;
+        try { await _worker.AbortMergeAsync(_taskId); }
+        catch (Exception ex) { Error = ex.Message; }
+        finally
+        {
+            IsBusy = false;
+            CloseRequested?.Invoke();
+        }
+    }
+}

src/ClaudeDo.Ui/ViewModels/IslandsShellViewModel.cs

@@ -44,6 +44,20 @@ public sealed partial class IslandsShellViewModel : ViewModelBase
     // Set by MainWindow to open the conflict resolution dialog.
     public Func<ConflictResolutionViewModel, Task>? ShowConflictDialog { get; set; }
 
+    // Layer C seam: composition root sets the factory; MainWindow sets the dialog opener.
+    // The integrator connects Layer A/B's RequestConflictResolution(taskId, target) to this method.
+    public Func<string, ClaudeDo.Ui.ViewModels.Conflicts.ConflictResolverViewModel>? ConflictResolverFactory { get; set; }
+    public Func<ClaudeDo.Ui.ViewModels.Conflicts.ConflictResolverViewModel, Task>? ShowConflictResolver { get; set; }
+
+    public async Task RequestConflictResolutionAsync(string taskId, string targetBranch)
+    {
+        if (ConflictResolverFactory is null || ShowConflictResolver is null) return;
+        var vm = ConflictResolverFactory(taskId);
+        var hasConflicts = await vm.OpenAsync(targetBranch);
+        if (hasConflicts)
+            await ShowConflictResolver(vm);
+    }
+
     // Set by MainWindow to open the About dialog.
     public Func<AboutModalViewModel, Task>? ShowAboutModal { get; set; }