feat(merge): fold parent branch into combined-diff for improvement parents

src/ClaudeDo.Worker/Planning/PlanningAggregator.cs

@@ -43,17 +43,24 @@ public sealed class PlanningAggregator
         string planningTaskId, CancellationToken ct)
     {
         using var ctx = _dbFactory.CreateDbContext();
-        var children = await ctx.Tasks
+        var parent = await ctx.Tasks
             .Include(t => t.Worktree)
-            .Where(t => t.ParentTaskId == planningTaskId)
+            .Include(t => t.Children).ThenInclude(c => c.Worktree)
-            .OrderBy(t => t.SortOrder)
+            .SingleOrDefaultAsync(t => t.Id == planningTaskId, ct);
-            .ToListAsync(ct);
+        if (parent is null) return new List<SubtaskDiff>();
+
+        var nodes = new List<TaskEntity>();
+        // An improvement parent carries its own code branch — fold it in first so the
+        // combined diff matches what the tree-merge will produce.
+        if (parent.PlanningPhase == PlanningPhase.None && parent.Worktree is { State: WorktreeState.Active })
+            nodes.Add(parent);
+        nodes.AddRange(parent.Children.OrderBy(c => c.SortOrder));
 
         var result = new List<SubtaskDiff>();
-        foreach (var child in children)
+        foreach (var node in nodes)
         {
-            if (child.Worktree is null) continue;
+            if (node.Worktree is null) continue;
-            var wt = child.Worktree;
+            var wt = node.Worktree;
             var head = wt.HeadCommit ?? await _git.RevParseHeadAsync(wt.Path, ct);
             string unified;
             try
@@ -62,11 +69,11 @@ public sealed class PlanningAggregator
             }
             catch (Exception ex)
             {
-                _logger.LogWarning(ex, "diff failed for subtask {Id}", child.Id);
+                _logger.LogWarning(ex, "diff failed for node {Id}", node.Id);
                 unified = "";
             }
             result.Add(new SubtaskDiff(
-                child.Id, child.Title, wt.BranchName, wt.BaseCommit, head, wt.DiffStat, unified));
+                node.Id, node.Title, wt.BranchName, wt.BaseCommit, head, wt.DiffStat, unified));
         }
         return result;
     }
@@ -87,12 +94,18 @@ public sealed class PlanningAggregator
 
         await GitRawAsync(repoDir, ct, "checkout", "-b", integrationBranch);
 
-        foreach (var child in childSubtasks)
+        var nodes = new List<TaskEntity>();
+        // Fold the improvement parent's own branch in first (planning parents have none).
+        if (planning.PlanningPhase == PlanningPhase.None && planning.Worktree is { State: WorktreeState.Active })
+            nodes.Add(planning);
+        nodes.AddRange(childSubtasks);
+
+        foreach (var node in nodes)
         {
-            if (child.Worktree is null) continue;
+            if (node.Worktree is null) continue;
             var (code, _) = await _git.MergeNoFfAsync(
-                repoDir, child.Worktree.BranchName,
+                repoDir, node.Worktree.BranchName,
-                $"Integrate subtask: {child.Title}", ct);
+                $"Integrate: {node.Title}", ct);
             if (code != 0)
             {
                 List<string> files;
@@ -104,7 +117,7 @@ public sealed class PlanningAggregator
                 try { await _git.BranchDeleteAsync(repoDir, integrationBranch, force: true, ct); } catch { }
 
                 return new CombinedDiffResult.Failed(
-                    new CombinedDiffFailure(child.Id, files));
+                    new CombinedDiffFailure(node.Id, files));
             }
         }
 
@@ -135,6 +148,7 @@ public sealed class PlanningAggregator
         using var ctx = _dbFactory.CreateDbContext();
         var planning = await ctx.Tasks
             .Include(t => t.List)
+            .Include(t => t.Worktree)
             .Include(t => t.Children).ThenInclude(c => c.Worktree)
             .SingleOrDefaultAsync(t => t.Id == planningTaskId, ct)
             ?? throw new KeyNotFoundException($"Planning task '{planningTaskId}' not found.");