feat(ui): collapse parent task rows by default with granular row sync

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

@@ -165,7 +165,7 @@ public class TasksIslandViewModelPlanningTests
         => new TaskRowViewModel { Id = id, Status = status, ParentTaskId = parentId, PlanningPhase = phase };
 
     [Fact]
-    public void ToggleExpand_CollapsesChildrenOfPlanningParent()
+    public void PlanningParentWithChildren_CollapsedByDefault_ToggleExpands()
     {
         var parent = MakeRow("p1", TaskStatus.Idle, phase: PlanningPhase.Active);
         var child1 = MakeRow("c1", TaskStatus.Idle, "p1");
@@ -173,18 +173,17 @@ public class TasksIslandViewModelPlanningTests
 
         var (vm, _) = VmFactory.Create([parent, child1, child2]);
 
-        // Initially expanded — children visible in OpenItems
-        Assert.Contains(child1, vm.OpenItems);
-        Assert.Contains(child2, vm.OpenItems);
-
-        // Collapse the parent
-        vm.ToggleExpandCommand.Execute(parent);
-
-        // Children should no longer appear
+        // Collapsed by default — children hidden, parent still present
         Assert.DoesNotContain(child1, vm.OpenItems);
         Assert.DoesNotContain(child2, vm.OpenItems);
-        // Parent still present
         Assert.Contains(parent, vm.OpenItems);
+
+        // Expand the parent
+        vm.ToggleExpandCommand.Execute(parent);
+
+        // Children now visible
+        Assert.Contains(child1, vm.OpenItems);
+        Assert.Contains(child2, vm.OpenItems);
     }
 
     [Fact]
@@ -210,20 +209,23 @@ public class TasksIslandViewModelPlanningTests
     }
 
     [Fact]
-    public void ToggleExpand_ExpandsCollapsedParentAgain()
+    public void ToggleExpand_TogglesParentExpansion()
     {
         var parent = MakeRow("p1", TaskStatus.Idle, phase: PlanningPhase.Finalized);
         var child = MakeRow("c1", TaskStatus.Idle, "p1");
 
         var (vm, _) = VmFactory.Create([parent, child]);
 
-        // Collapse
-        vm.ToggleExpandCommand.Execute(parent);
+        // Collapsed by default
         Assert.DoesNotContain(child, vm.OpenItems);
 
-        // Re-expand
+        // Expand
         vm.ToggleExpandCommand.Execute(parent);
         Assert.Contains(child, vm.OpenItems);
+
+        // Collapse again
+        vm.ToggleExpandCommand.Execute(parent);
+        Assert.DoesNotContain(child, vm.OpenItems);
     }
 
     [Fact]