feat(D.5.1): ToolbarController — bind 18 slots, populate, deferred rebind, click-to-use

Port of gmToolbarUI::PostInit (slot wiring) + UpdateFromPlayerDesc (flush-and-bind
shortcuts from PlayerDescription) + SetDelayedShortcutNum (deferred ItemAdded rebind)
+ UseShortcut (click → useItem callback).

UiItemSlot gains Clicked (Action?) + OnEvent override (MouseDown → Clicked?.Invoke())
matching the retail UIElement_UIItem click dispatch pattern. UiEvent is a positional
record struct so the OnEvent override reads e.Type (int) against UiEventType.MouseDown
(const int 0x201) — confirmed from UiEvent.cs + UiText.cs before writing.

Three tests green (populate bound slot, deferred rebind on ItemAdded, click fires useItem).
Full suite: 0 failures.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

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

@@ -0,0 +1,85 @@
+using System;
+using System.Collections.Generic;
+using AcDream.App.UI;
+using AcDream.App.UI.Layout;
+using AcDream.Core.Items;
+using AcDream.Core.Net.Messages;
+using Xunit;
+
+namespace AcDream.App.Tests.UI.Layout;
+
+public class ToolbarControllerTests
+{
+    private static readonly uint[] Row1 =
+        { 0x100001A7,0x100001A8,0x100001A9,0x100001AA,0x100001AB,0x100001AC,0x100001AD,0x100001AE,0x100001AF };
+    private static readonly uint[] Row2 =
+        { 0x100006B7,0x100006B8,0x100006B9,0x100006BA,0x100006BB,0x100006BC,0x100006BD,0x100006BE,0x100006BF };
+
+    private static (ImportedLayout layout, Dictionary<uint, UiItemList> slots) FakeToolbar()
+    {
+        var dict = new Dictionary<uint, UiElement>();
+        var slots = new Dictionary<uint, UiItemList>();
+        var root = new UiPanel();
+        foreach (var id in Row1) AddSlot(id);
+        foreach (var id in Row2) AddSlot(id);
+        return (new ImportedLayout(root, dict), slots);
+
+        void AddSlot(uint id)
+        {
+            var list = new UiItemList(_ => (0u, 0, 0)) { Width = 32, Height = 32 };
+            dict[id] = list; slots[id] = list; root.AddChild(list);
+        }
+    }
+
+    [Fact]
+    public void Populate_bindsShortcutToCorrectSlot()
+    {
+        var (layout, slots) = FakeToolbar();
+        var repo = new ItemRepository();
+        repo.AddOrUpdate(new ItemInstance { ObjectId = 0x5001u, WeenieClassId = 1u, IconId = 0x06001234u });
+        var shortcuts = new List<PlayerDescriptionParser.ShortcutEntry>
+        { new(Index: 0, ObjectGuid: 0x5001u, SpellId: 0, Layer: 0) };
+
+        ToolbarController.Bind(layout, repo, () => shortcuts,
+            iconIds: (_,_,_) => 0x77u, useItem: _ => { });
+
+        Assert.Equal(0x5001u, slots[Row1[0]].Cell.ItemId);
+        Assert.Equal(0x77u,   slots[Row1[0]].Cell.IconTexture);
+        Assert.Equal(0u,      slots[Row1[1]].Cell.ItemId); // others empty
+    }
+
+    [Fact]
+    public void DeferredRebind_whenItemArrivesLate()
+    {
+        var (layout, slots) = FakeToolbar();
+        var repo = new ItemRepository(); // item NOT present yet
+        var shortcuts = new List<PlayerDescriptionParser.ShortcutEntry>
+        { new(Index: 2, ObjectGuid: 0x5002u, SpellId: 0, Layer: 0) };
+
+        ToolbarController.Bind(layout, repo, () => shortcuts,
+            iconIds: (_,_,_) => 0x88u, useItem: _ => { });
+        Assert.Equal(0u, slots[Row1[2]].Cell.ItemId); // not bound yet
+
+        repo.AddOrUpdate(new ItemInstance { ObjectId = 0x5002u, WeenieClassId = 1u, IconId = 0x06005678u });
+
+        Assert.Equal(0x5002u, slots[Row1[2]].Cell.ItemId); // rebound on ItemAdded
+    }
+
+    [Fact]
+    public void Click_emitsUseForBoundItem()
+    {
+        var (layout, slots) = FakeToolbar();
+        var repo = new ItemRepository();
+        repo.AddOrUpdate(new ItemInstance { ObjectId = 0x5001u, WeenieClassId = 1u, IconId = 0x06001234u });
+        var shortcuts = new List<PlayerDescriptionParser.ShortcutEntry>
+        { new(Index: 0, ObjectGuid: 0x5001u, SpellId: 0, Layer: 0) };
+        uint used = 0;
+
+        ToolbarController.Bind(layout, repo, () => shortcuts,
+            iconIds: (_,_,_) => 0x77u, useItem: g => used = g);
+        // UiEvent is a positional record struct: (SourceId, Target, Type, Data0..3, Payload)
+        slots[Row1[0]].Cell.OnEvent(new UiEvent(0u, null, UiEventType.MouseDown));
+
+        Assert.Equal(0x5001u, used);
+    }
+}