feat(worker): add ContinueMergeAsync to resume a conflicted merge

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/ClaudeDo.Worker/Services/TaskMergeService.cs

@@ -155,6 +155,44 @@ public sealed class TaskMergeService
         CancellationToken ct)
         => MergeAsync(taskId, targetBranch, removeWorktree, commitMessage, leaveConflictsInTree: false, ct);
 
+    public async Task<MergeResult> ContinueMergeAsync(string taskId, CancellationToken ct)
+    {
+        TaskEntity task;
+        ListEntity list;
+        WorktreeEntity? wt;
+
+        using (var ctx = _dbFactory.CreateDbContext())
+        {
+            task = await new TaskRepository(ctx).GetByIdAsync(taskId, ct)
+                ?? throw new KeyNotFoundException($"Task '{taskId}' not found.");
+            list = await new ListRepository(ctx).GetByIdAsync(task.ListId, ct)
+                ?? throw new InvalidOperationException("List not found.");
+            wt = await new WorktreeRepository(ctx).GetByTaskIdAsync(taskId, ct);
+        }
+
+        if (wt is null) return Blocked("task has no worktree");
+        if (string.IsNullOrWhiteSpace(list.WorkingDir)) return Blocked("list has no working directory");
+        if (!await _git.IsMidMergeAsync(list.WorkingDir, ct))
+            return Blocked("repo is not mid-merge");
+
+        await _git.AddAllAsync(list.WorkingDir, ct);
+
+        var remaining = await _git.ListConflictedFilesAsync(list.WorkingDir, ct);
+        if (remaining.Count > 0)
+            return new MergeResult(StatusConflict, remaining, "conflicts not fully resolved");
+
+        await _git.CommitAsync(list.WorkingDir, $"Merge branch '{wt.BranchName}'", ct);
+
+        using (var ctx = _dbFactory.CreateDbContext())
+        {
+            await new WorktreeRepository(ctx).SetStateAsync(taskId, WorktreeState.Merged, ct);
+        }
+        await _broadcaster.WorktreeUpdated(taskId);
+        _logger.LogInformation("Continued merge of task {TaskId} branch {Branch}", taskId, wt.BranchName);
+
+        return new MergeResult(StatusMerged, Array.Empty<string>(), null);
+    }
+
     public async Task<MergeTargets> GetTargetsAsync(string taskId, CancellationToken ct)
     {
         TaskEntity task;