fix(ui): restore retail spell tabs and spellbook

Bind the spellbook and component-book tabs as their authored stateful text controls, propagate Closed/Open state into the retained DAT child tree, and keep authored label colors live across state changes.

Match retail UIElement_Text zero-margin construction so the Magic favorite captions I through VIII are no longer clipped. Add a real portal.dat spellbook fixture plus controller, state-propagation, and text-layout regression coverage.

Co-Authored-By: Codex <noreply@openai.com>

tests/AcDream.App.Tests/UI/Layout/SpellbookWindowControllerTests.cs

@@ -0,0 +1,56 @@
+using AcDream.App.Spells;
+using AcDream.App.UI;
+using AcDream.App.UI.Layout;
+using AcDream.Core.Items;
+using AcDream.Core.Spells;
+
+namespace AcDream.App.Tests.UI.Layout;
+
+public sealed class SpellbookWindowControllerTests
+{
+    [Fact]
+    public void RetailFixture_BindsTextTabs_AndPropagatesOpenClosedState()
+    {
+        ImportedLayout layout = FixtureLoader.LoadSpellbook();
+        var closed = new List<uint>();
+        using SpellbookWindowController? controller = SpellbookWindowController.Bind(
+            layout,
+            new Spellbook(),
+            new ClientObjectTable(),
+            () => 1u,
+            new Dictionary<uint, SpellComponentDescriptor>(),
+            spellId => spellId,
+            iconId => iconId,
+            _ => 1,
+            _ => { },
+            _ => { },
+            _ => { },
+            (_, _) => { },
+            () => closed.Add(1u));
+
+        Assert.NotNull(controller);
+        UiText spellTab = Assert.IsType<UiText>(layout.FindElement(SpellbookWindowController.SpellTabId));
+        UiText componentTab = Assert.IsType<UiText>(layout.FindElement(SpellbookWindowController.ComponentTabId));
+        UiElement spellPage = Assert.IsAssignableFrom<UiElement>(layout.FindElement(SpellbookWindowController.SpellPageId));
+        UiElement componentPage = Assert.IsAssignableFrom<UiElement>(layout.FindElement(SpellbookWindowController.ComponentPageId));
+
+        Assert.Equal(RetailUiStateIds.Open, spellTab.ActiveRetailStateId);
+        Assert.Equal(RetailUiStateIds.Closed, componentTab.ActiveRetailStateId);
+        Assert.True(spellPage.Visible);
+        Assert.False(componentPage.Visible);
+        Assert.Equal(3, spellTab.Children.Count);
+        Assert.All(spellTab.Children, child =>
+            Assert.Equal(RetailUiStateIds.Open, Assert.IsAssignableFrom<IUiDatStateful>(child).ActiveRetailStateId));
+
+        componentTab.OnEvent(new UiEvent(0, componentTab, UiEventType.Click));
+
+        Assert.Equal(SpellbookWindowPage.Components, controller!.CurrentPage);
+        Assert.Equal(RetailUiStateIds.Closed, spellTab.ActiveRetailStateId);
+        Assert.Equal(RetailUiStateIds.Open, componentTab.ActiveRetailStateId);
+        Assert.False(spellPage.Visible);
+        Assert.True(componentPage.Visible);
+        Assert.All(componentTab.Children, child =>
+            Assert.Equal(RetailUiStateIds.Open, Assert.IsAssignableFrom<IUiDatStateful>(child).ActiveRetailStateId));
+        Assert.Empty(closed);
+    }
+}