feat(ui): My Day actions, orphan-aware grouping, menu restructure

Pending UI work:
- My Day add/remove context actions on task rows (parent removal cascades to children)
- orphan-aware grouping: a child whose parent isn't in view renders as a top-level row, not an indented draft
- shell menu restructure (Worker / Repositories submenus); 'Finalize plan' action, drop 'Queue subtasks sequentially'
- notes editor refinements
- subtask-row hover tweak (Surface3, no transition)
- bump Avalonia 12.0.0 -> 12.0.4

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

@@ -109,4 +109,83 @@ public class TaskRowViewModelPlanningTests
         var vm = MakeRow(TaskStatus.Idle, phase: PlanningPhase.Finalized);
         Assert.False(vm.CanQueuePlan);
     }
+
+    [Fact]
+    public void ActivePlanningParent_CannotSendToQueue()
+    {
+        var vm = MakeRow(TaskStatus.Idle, phase: PlanningPhase.Active);
+        vm.HasPlanningChildren = true;
+        Assert.False(vm.CanSendToQueue);
+    }
+
+    [Fact]
+    public void FinalizedParentWithChildren_CanSendToQueue()
+    {
+        var vm = MakeRow(TaskStatus.Idle, phase: PlanningPhase.Finalized);
+        vm.HasPlanningChildren = true;
+        Assert.True(vm.CanSendToQueue);
+    }
+
+    [Fact]
+    public void ActivePlanning_CanFinalizePlanning()
+    {
+        var vm = MakeRow(TaskStatus.Idle, phase: PlanningPhase.Active);
+        Assert.True(vm.CanFinalizePlanning);
+    }
+
+    [Fact]
+    public void FinalizedPlanning_CannotFinalizePlanning()
+    {
+        var vm = MakeRow(TaskStatus.Idle, phase: PlanningPhase.Finalized);
+        Assert.False(vm.CanFinalizePlanning);
+    }
+
+    [Fact]
+    public void PlainIdle_CannotFinalizePlanning()
+    {
+        var vm = MakeRow(TaskStatus.Idle);
+        Assert.False(vm.CanFinalizePlanning);
+    }
+
+    [Fact]
+    public void ChildWithParentInView_RendersAsChild()
+    {
+        var vm = MakeRow(TaskStatus.Idle, parentTaskId: "parent-id");
+        Assert.True(vm.ParentInView);   // default
+        Assert.True(vm.ShowAsChild);
+        Assert.True(vm.IsDraft);
+    }
+
+    [Fact]
+    public void OrphanedChild_RendersFlat_WithNoDraftOrPlannedBadge()
+    {
+        // Parent absent from the view (e.g. removed from My Day, or daily-prep placed a lone
+        // child there): the row stays a child by data but must read as a normal top-level task.
+        var draftOrphan = MakeRow(TaskStatus.Idle, parentTaskId: "missing");
+        draftOrphan.ParentInView = false;
+        Assert.True(draftOrphan.IsChild);
+        Assert.False(draftOrphan.ShowAsChild);
+        Assert.False(draftOrphan.IsDraft);
+
+        var plannedOrphan = MakeRow(TaskStatus.Idle, parentTaskId: "missing");
+        plannedOrphan.ParentFinalized = true;
+        plannedOrphan.ParentInView = false;
+        Assert.False(plannedOrphan.ShowAsChild);
+        Assert.False(plannedOrphan.IsPlanned);
+        Assert.False(plannedOrphan.IsDraft);
+    }
+
+    [Fact]
+    public void CanAddToMyDay_TrueOnlyWhenNotInMyDayAndNotDone()
+    {
+        var row = MakeRow(TaskStatus.Idle);
+        Assert.True(row.CanAddToMyDay);   // idle, not yet in My Day
+
+        row.IsMyDay = true;
+        Assert.False(row.CanAddToMyDay);  // already in My Day
+
+        row.IsMyDay = false;
+        row.Done = true;
+        Assert.False(row.CanAddToMyDay);  // done tasks don't belong in today's focus
+    }
 }