feat(children): generalize CreateChildAsync for any parent + CreatedBy stamp

src/ClaudeDo.Data/Repositories/TaskRepository.cs

@@ -196,6 +196,7 @@ public sealed class TaskRepository
         string title,
         string? description,
         string? commitType,
+        string? createdBy = null,
         CancellationToken ct = default)
     {
         // AsNoTracking: SetPlanningStartedAsync mutates via ExecuteUpdate which
@@ -204,9 +205,6 @@ public sealed class TaskRepository
             .FirstOrDefaultAsync(t => t.Id == parentId, ct);
         if (parent is null)
             throw new InvalidOperationException($"Parent task {parentId} not found.");
-        if (parent.PlanningPhase == PlanningPhase.None)
-            throw new InvalidOperationException(
-                $"Parent task {parentId} is not in a planning phase; cannot attach children.");
 
         var maxSort = await _context.Tasks
             .Where(t => t.ListId == parent.ListId)
@@ -224,6 +222,7 @@ public sealed class TaskRepository
             CommitType = string.IsNullOrEmpty(commitType) ? parent.CommitType : commitType,
             ParentTaskId = parentId,
             SortOrder = (maxSort ?? -1) + 1,
+            CreatedBy = createdBy,
         };
         _context.Tasks.Add(child);
         await _context.SaveChangesAsync(ct);