feat(ui): port retail toolbar ammo count

Resolve stacked thrown weapons versus separately equipped missile ammo exactly like gmToolbarUI, normalize a zero stack to one, and refresh the authored missile indicator from equipment and stack events. Keep the decision in pure Core with retained and real-DAT conformance coverage.

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

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

@@ -336,6 +336,17 @@ public class ToolbarControllerTests
         }
     }
 
+    [Fact]
+    public void RetailFixture_ammoNumberUsesAuthoredMissileIndicatorElement()
+    {
+        ImportedLayout layout = FixtureLoader.LoadToolbar();
+
+        var ammoIndicator = Assert.IsType<UiButton>(layout.FindElement(0x10000194u));
+
+        Assert.Equal(55f, ammoIndicator.Width);
+        Assert.Equal(58f, ammoIndicator.Height);
+    }
+
     [Fact]
     public void UseAndExamineButtons_dispatchSelectedObjectPolicy()
     {
@@ -387,6 +398,76 @@ public class ToolbarControllerTests
 
     // ── C1: combat-mode indicator tests ─────────────────────────────────────
 
+    [Fact]
+    public void AmmoNumber_usesStackableMissileWeapon_andTracksStackChanges()
+    {
+        const uint player = 0x50000001u;
+        const uint thrownWeapon = 0x50000002u;
+        const uint separateAmmo = 0x50000003u;
+        var (layout, _, _) = FakeToolbar();
+        var repo = new ClientObjectTable();
+        repo.AddOrUpdate(new ClientObject { ObjectId = player, Type = ItemType.Creature });
+        repo.AddOrUpdate(new ClientObject
+        {
+            ObjectId = thrownWeapon,
+            StackSize = 7,
+            StackSizeMax = 25,
+        });
+        repo.MoveItem(thrownWeapon, player, newEquipLocation: EquipMask.MissileWeapon);
+        repo.AddOrUpdate(new ClientObject
+        {
+            ObjectId = separateAmmo,
+            StackSize = 80,
+            StackSizeMax = 100,
+        });
+        repo.MoveItem(separateAmmo, player, newEquipLocation: EquipMask.MissileAmmo);
+
+        ToolbarController.Bind(
+            layout,
+            repo,
+            () => Array.Empty<ShortcutEntry>(),
+            iconIds: (_, _, _, _, _) => 0u,
+            useItem: _ => { },
+            playerGuid: () => player);
+        var ammoButton = (UiButton)layout.FindElement(0x10000194u)!;
+
+        Assert.Equal("7", ammoButton.Label);
+
+        Assert.True(repo.UpdateStackSize(thrownWeapon, 6, value: 0));
+        Assert.Equal("6", ammoButton.Label);
+    }
+
+    [Fact]
+    public void AmmoNumber_forLauncher_usesAmmoSlot_andClearsOnUnwield()
+    {
+        const uint player = 0x50000001u;
+        const uint pack = 0x50000010u;
+        const uint bow = 0x50000002u;
+        const uint arrows = 0x50000003u;
+        var (layout, _, _) = FakeToolbar();
+        var repo = new ClientObjectTable();
+        repo.AddOrUpdate(new ClientObject { ObjectId = player, Type = ItemType.Creature });
+        repo.AddOrUpdate(new ClientObject { ObjectId = pack, Type = ItemType.Container });
+        repo.AddOrUpdate(new ClientObject { ObjectId = bow, StackSize = 1, StackSizeMax = 1 });
+        repo.MoveItem(bow, player, newEquipLocation: EquipMask.MissileWeapon);
+        repo.AddOrUpdate(new ClientObject { ObjectId = arrows, StackSize = 42, StackSizeMax = 100 });
+        repo.MoveItem(arrows, player, newEquipLocation: EquipMask.MissileAmmo);
+
+        ToolbarController.Bind(
+            layout,
+            repo,
+            () => Array.Empty<ShortcutEntry>(),
+            iconIds: (_, _, _, _, _) => 0u,
+            useItem: _ => { },
+            playerGuid: () => player);
+        var ammoButton = (UiButton)layout.FindElement(0x10000194u)!;
+
+        Assert.Equal("42", ammoButton.Label);
+
+        Assert.True(repo.MoveItem(arrows, pack));
+        Assert.Null(ammoButton.Label);
+    }
+
     [Fact]
     public void CombatIndicators_allDispatchSharedRetailToggleCommand()
     {

tests/AcDream.Core.Tests/Items/ToolbarAmmoPolicyTests.cs

@@ -0,0 +1,65 @@
+using AcDream.Core.Items;
+
+namespace AcDream.Core.Tests.Items;
+
+public sealed class ToolbarAmmoPolicyTests
+{
+    [Fact]
+    public void StackableMissileWeapon_isItsOwnAmmo()
+    {
+        var thrown = Item(1u, EquipMask.MissileWeapon, stack: 7, maxStack: 25);
+        var separateAmmo = Item(2u, EquipMask.MissileAmmo, stack: 80, maxStack: 100);
+
+        ToolbarAmmoPolicy.Result result = ToolbarAmmoPolicy.Resolve(
+            new[] { thrown, separateAmmo });
+
+        Assert.Equal(new ToolbarAmmoPolicy.Result(1u, 7), result);
+    }
+
+    [Fact]
+    public void NonStackableLauncher_usesSeparateAmmoSlot()
+    {
+        var bow = Item(1u, EquipMask.MissileWeapon, stack: 1, maxStack: 1);
+        var arrows = Item(2u, EquipMask.MissileAmmo, stack: 42, maxStack: 100);
+
+        ToolbarAmmoPolicy.Result result = ToolbarAmmoPolicy.Resolve(
+            new[] { bow, arrows });
+
+        Assert.Equal(new ToolbarAmmoPolicy.Result(2u, 42), result);
+    }
+
+    [Fact]
+    public void MissingAmmo_isHidden_andWireZeroStackDisplaysOne()
+    {
+        Assert.Equal(default, ToolbarAmmoPolicy.Resolve(Array.Empty<ClientObject>()));
+
+        var arrows = Item(3u, EquipMask.MissileAmmo, stack: 0, maxStack: 100);
+        Assert.Equal(
+            new ToolbarAmmoPolicy.Result(3u, 1),
+            ToolbarAmmoPolicy.Resolve(new[] { arrows }));
+    }
+
+    [Fact]
+    public void FirstIntersectingInventoryPlacementWins()
+    {
+        var first = Item(1u, EquipMask.MissileAmmo | EquipMask.Held, stack: 10, maxStack: 100);
+        var second = Item(2u, EquipMask.MissileAmmo, stack: 20, maxStack: 100);
+
+        Assert.Equal(
+            new ToolbarAmmoPolicy.Result(1u, 10),
+            ToolbarAmmoPolicy.Resolve(new[] { first, second }));
+    }
+
+    private static ClientObject Item(
+        uint id,
+        EquipMask location,
+        int stack,
+        int maxStack)
+        => new()
+        {
+            ObjectId = id,
+            CurrentlyEquippedLocation = location,
+            StackSize = stack,
+            StackSizeMax = maxStack,
+        };
+}