feat(worker): let review_task/merge_task leave conflicts in tree via MCP

src/ClaudeDo.Worker/Lifecycle/TaskMergeService.cs

@@ -342,7 +342,11 @@ public sealed class TaskMergeService
         return new MergePreviewResult(PreviewClean, Array.Empty<string>(), count);
     }
 
-    public async Task<MergeResult> ApproveAndMergeAsync(string taskId, string targetBranch, CancellationToken ct)
+    public Task<MergeResult> ApproveAndMergeAsync(string taskId, string targetBranch, CancellationToken ct)
+        => ApproveAndMergeAsync(taskId, targetBranch, leaveConflictsInTree: false, ct);
+
+    public async Task<MergeResult> ApproveAndMergeAsync(
+        string taskId, string targetBranch, bool leaveConflictsInTree, CancellationToken ct)
     {
         var (task, list, wt) = await LoadMergeContextAsync(taskId, ct);
 
@@ -367,7 +371,7 @@ public sealed class TaskMergeService
         // MergeAsync transitions the task WaitingForReview -> Done on a successful merge.
         // Remove the worktree on approve (matching the unit-merge path) so merged
         // worktrees don't pile up; the merge commit on the target branch is the record.
-        return await MergeAsync(taskId, target, removeWorktree: true, $"Merge {wt.BranchName}", ct);
+        return await MergeAsync(taskId, target, removeWorktree: true, $"Merge {wt.BranchName}", leaveConflictsInTree, ct);
     }
 
     private static MergeResult Blocked(string reason) =>