fix(ui): restore retail magic shortcut bar

Port the retail horizontal ItemList empty-slot padding and share UIItem shortcut-number graphics with the status toolbar. Preserve all authored face children on compound DAT buttons so the three-piece Cast control reflows and renders as one complete button.

Co-authored-by: OpenAI Codex <codex@openai.com>

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

@@ -11,6 +11,60 @@ public sealed class SpellcastingUiControllerTests
 {
     private static (uint, int, int) NoTex(uint _) => (0u, 0, 0);
 
+    [Fact]
+    public void ImportedFixture_UsesRetailEmptyCells_ShortcutDigits_AndCompleteCastButton()
+    {
+        ImportedLayout layout = LayoutImporter.Build(
+            FixtureLoader.LoadCombatInfos(), NoTex, datFont: null);
+        ApplyAnchors(layout.Root);
+        var spellbook = new Spellbook();
+        spellbook.OnSpellLearned(42u, 1f);
+        spellbook.SetFavorite(0, 0, 42u);
+        var objects = new ClientObjectTable();
+        objects.AddOrUpdate(new ClientObject { ObjectId = 1u, Name = "Player" });
+        uint[] regular = [101u, 102u, 103u, 104u, 105u, 106u, 107u, 108u, 109u];
+        uint[] ghosted = [201u, 202u, 203u, 204u, 205u, 206u, 207u, 208u, 209u];
+        uint[] empty = [301u, 302u, 303u, 304u, 305u, 306u, 307u, 308u, 309u];
+        var graphics = new UiShortcutSlotGraphics(regular, ghosted, empty, 0x060074CFu);
+
+        using SpellcastingUiController controller = Bind(
+            layout, spellbook, objects, _ => { }, shortcutGraphics: graphics)!;
+
+        UiElement group = layout.FindElement(0x100000AAu)!;
+        UiItemList list = Descendants(group).OfType<UiItemList>().First();
+        Assert.True(list.SingleRow);
+        Assert.True(list.FillVisibleEmptySlots);
+        Assert.Equal(439f, list.Width);
+        Assert.Equal(13, list.GetNumUIItems());
+
+        UiCatalogSlot favorite = Assert.IsType<UiCatalogSlot>(list.GetItem(0));
+        Assert.Equal(42u, favorite.EntryId);
+        Assert.Equal(0, favorite.ShortcutNum);
+        Assert.Same(regular, favorite.ActiveDigitArray());
+
+        for (int i = 1; i < 9; i++)
+        {
+            UiCatalogSlot slot = Assert.IsType<UiCatalogSlot>(list.GetItem(i));
+            Assert.True(slot.IsEmptySlot);
+            Assert.Equal(i, slot.ShortcutNum);
+            Assert.Same(empty, slot.ActiveDigitArray());
+        }
+        for (int i = 9; i < 13; i++)
+            Assert.Equal(-1, list.GetItem(i)!.ShortcutNum);
+
+        var cast = Assert.IsType<UiButton>(
+            layout.FindElement(SpellcastingUiController.CastButtonId));
+        Assert.Equal((525f, 75f), (cast.Left, cast.Width));
+        Assert.Equal(3, cast.FaceSegmentCount);
+        Assert.Equal(
+            [
+                new UiPixelRect(0, 0, 31, 31),
+                new UiPixelRect(32, 0, 42, 31),
+                new UiPixelRect(43, 0, 74, 31),
+            ],
+            cast.FaceSegmentRectsForTest());
+    }
+
     [Fact]
     public void ImportedFixture_BindsAllTabs_AndTracksEquippedEndowment()
     {
@@ -167,7 +221,8 @@ public sealed class SpellcastingUiControllerTests
         Spellbook spellbook,
         ClientObjectTable objects,
         Action<uint> useItem,
-        Action<int, int, uint>? addFavorite = null)
+        Action<int, int, uint>? addFavorite = null,
+        UiShortcutSlotGraphics? shortcutGraphics = null)
     {
         var casting = new SpellCastingController(
             spellbook, () => null, () => 1u, () => { }, _ => { }, (_, _) => { }, _ => { });
@@ -178,7 +233,17 @@ public sealed class SpellcastingUiControllerTests
             useItem,
             new SelectionState(),
             addFavorite ?? ((_, _, _) => { }),
-            (_, _) => { });
+            (_, _) => { },
+            shortcutGraphics);
+    }
+
+    private static void ApplyAnchors(UiElement parent)
+    {
+        foreach (UiElement child in parent.Children)
+        {
+            child.ApplyAnchor(parent.Width, parent.Height);
+            ApplyAnchors(child);
+        }
     }
 
     private static IEnumerable<UiElement> Descendants(UiElement root)

tests/AcDream.App.Tests/UI/UiItemListTests.cs

@@ -61,6 +61,38 @@ public class UiItemListTests
         Assert.Equal((17, 9), (received.Value.X, received.Value.Y));
     }
 
+    [Fact]
+    public void RetailHorizontalEmptySlots_FillViewport_AndShrinkOnlyEmptyTail()
+    {
+        var list = new UiItemList
+        {
+            Width = 130f,
+            Height = 32f,
+            CellWidth = 32f,
+            CellHeight = 32f,
+            SingleRow = true,
+            FillVisibleEmptySlots = true,
+            EmptySlotFactory = () => new UiCatalogSlot(),
+        };
+        list.Flush();
+        list.AddItem(new UiCatalogSlot { EntryId = 42u });
+        list.LayoutCells();
+
+        Assert.Equal(4, list.GetNumUIItems());
+        Assert.Equal((0f, 32f, 64f, 96f),
+            (list.GetItem(0)!.Left, list.GetItem(1)!.Left,
+             list.GetItem(2)!.Left, list.GetItem(3)!.Left));
+
+        list.Width = 65f;
+        list.LayoutCells();
+        Assert.Equal(2, list.GetNumUIItems());
+        Assert.Equal(42u, Assert.IsType<UiCatalogSlot>(list.GetItem(0)).EntryId);
+
+        list.Width = 16f;
+        list.LayoutCells();
+        Assert.Single(list.Children); // the occupied cell is never discarded
+    }
+
     [Fact]
     public void ScrollItemIntoView_moves_only_when_row_is_outside_viewport()
     {