feat(ui): port retail component book rows

Instantiate gmSpellComponentUI category and component entries from LayoutDesc 0x21000033 instead of synthesizing catalog rows. Preserve localized category titles, authored textures and geometry, live icon/count/desired bindings, selected-object synchronization, and retail's inclusive 0..5000 desired-level contract.

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

src/AcDream.App/UI/UiTextureElement.cs

@@ -0,0 +1,23 @@
+using System.Numerics;
+using AcDream.App.Rendering;
+
+namespace AcDream.App.UI;
+
+/// <summary>
+/// Runtime-owned texture content inside an authored retained-UI region. LayoutDesc
+/// still owns the region's geometry and chrome; controllers supply only the live
+/// texture handle (for example a composed item icon).
+/// </summary>
+public sealed class UiTextureElement : UiElement
+{
+    public UiTextureElement() => ClickThrough = true;
+
+    public uint Texture { get; set; }
+    public Vector4 Tint { get; set; } = Vector4.One;
+
+    protected override void OnDraw(UiRenderContext ctx)
+    {
+        if (Texture != 0u)
+            ctx.DrawSprite(Texture, 0f, 0f, Width, Height, 0f, 0f, 1f, 1f, Tint);
+    }
+}