feat(daily-prep): trigger planning from inside the prep-log window with an empty-state hint

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

tests/ClaudeDo.Ui.Tests/ViewModels/TasksIslandDailyPrepTests.cs

@@ -53,15 +53,4 @@ public class TasksIslandDailyPrepTests : IDisposable
         Assert.Equal(1, stub.ClearMyDayCalls);
     }
 
-    [Fact]
-    public async Task PrepareDayCommand_raises_PrepRequested()
-    {
-        var vm = NewTasksVm(new DefaultStub());
-        var raised = false;
-        vm.PrepRequested += () => raised = true;
-
-        await vm.PrepareDayCommand.ExecuteAsync(null);
-
-        Assert.True(raised);
-    }
 }