feat(ui): TaskRowViewModel gains planning hierarchy flags

Adds ParentTaskId, IsExpanded, IsChild, IsPlanningParent, IsDraft, and
PlanningBadge to TaskRowViewModel with property-changed notifications.

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

tests/ClaudeDo.Worker.Tests/UiVm/TaskRowViewModelPlanningTests.cs

@@ -0,0 +1,45 @@
+using ClaudeDo.Data.Models;
+using ClaudeDo.Ui.ViewModels.Islands;
+using Xunit;
+using TaskStatus = ClaudeDo.Data.Models.TaskStatus;
+
+namespace ClaudeDo.Worker.Tests.UiVm;
+
+public class TaskRowViewModelPlanningTests
+{
+    private static TaskRowViewModel MakeRow(TaskStatus status, string? parentTaskId = null)
+        => new TaskRowViewModel { Id = "t", Status = status, ParentTaskId = parentTaskId };
+
+    [Fact]
+    public void Draft_Status_SetsIsChildFlag_WhenParentIdIsNotNull()
+    {
+        var vm = MakeRow(TaskStatus.Draft, "parent-id");
+        Assert.True(vm.IsChild);
+        Assert.False(vm.IsPlanningParent);
+    }
+
+    [Fact]
+    public void Planning_Status_SetsIsPlanningParent()
+    {
+        var vm = MakeRow(TaskStatus.Planning);
+        Assert.True(vm.IsPlanningParent);
+        Assert.False(vm.IsChild);
+        Assert.Equal("PLANNING", vm.PlanningBadge);
+    }
+
+    [Fact]
+    public void Planned_Status_ShowsPlannedBadge()
+    {
+        var vm = MakeRow(TaskStatus.Planned);
+        Assert.True(vm.IsPlanningParent);
+        Assert.Equal("PLANNED", vm.PlanningBadge);
+    }
+
+    [Fact]
+    public void NonPlanningStatus_NoBadge()
+    {
+        var vm = MakeRow(TaskStatus.Manual);
+        Assert.False(vm.IsPlanningParent);
+        Assert.Null(vm.PlanningBadge);
+    }
+}