feat(D.2b): Slice 2 — paperdoll armor/non-armor partition + Slots toggle state

Adds ArmorSlotElementIds (the exact 9 ids gmPaperDollUI::ListenToElementMessage
flips per decomp 175674-175706) and PaperdollViewState (SlotView/DollVisible/
ArmorSlotsVisible/Toggle) as a nested public class on PaperdollController.

Wires ApplyView() into the constructor so the Slots button (0x100005BE) drives
armor-slot Visible and the doll viewport Visible on every click. Initial state
is doll-view (armor slots hidden). The doll viewport element (0x100001D5) is
bound as UiElement? so this slice stays independent of Slice 3's IUiViewportRenderer
seam; _armorSlots collects whichever of the 9 ids were found in the live layout.

Three new unit tests verify the id set, the default state, and the round-trip
toggle against the public PaperdollViewState surface only.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/AcDream.App/UI/Layout/PaperdollController.cs

@@ -14,6 +14,32 @@ namespace AcDream.App.UI.Layout;
 /// </summary>
 public sealed class PaperdollController : IItemListDragHandler
 {
+    // ── Slots-toggle public surface ───────────────────────────────────────────────────────────────
+    /// <summary>
+    /// The 9 armor-slot element-ids whose Visible state the Slots button (0x100005BE) toggles.
+    /// Doll-view: hidden. Slot-view: shown.  Source: gmPaperDollUI::ListenToElementMessage decomp
+    /// 175674-175706 — these are the only 9 ids that element flips; the other ~12 equip slots
+    /// (jewelry, weapon, wrists, feet…) are NON-armor and remain visible in both views.
+    /// </summary>
+    public static readonly uint[] ArmorSlotElementIds =
+    {
+        0x100005abu, 0x100005acu, 0x100005adu, 0x100005aeu, 0x100005afu,
+        0x100005b0u, 0x100005b1u, 0x100005b2u, 0x100005b3u,
+    };
+
+    /// <summary>
+    /// View-state model for the Slots toggle (pure logic, no UI coupling).
+    /// Default is doll-view (SlotView == false): the 3-D character is visible,
+    /// the 9 armor slots are hidden.  Calling Toggle() alternates between views.
+    /// </summary>
+    public sealed class PaperdollViewState
+    {
+        public bool SlotView { get; private set; }          // false = doll-view (default)
+        public bool DollVisible    => !SlotView;
+        public bool ArmorSlotsVisible => SlotView;
+        public void Toggle() => SlotView = !SlotView;
+    }
+
     // WEAPON_READY_SLOT_LOC (acclient.h:3235): the weapon-hand doll slot accepts any wieldable weapon.
     private const EquipMask WeaponSlotMask =
         EquipMask.MeleeWeapon | EquipMask.MissileWeapon | EquipMask.Held | EquipMask.TwoHanded;
@@ -51,6 +77,11 @@ public sealed class PaperdollController : IItemListDragHandler
     private readonly Action<uint, uint>? _sendWield;     // (itemGuid, equipMask) → GetAndWieldItem 0x001A
     private readonly List<(EquipMask Mask, UiItemList List)> _slots = new();
 
+    // ── Slots-toggle state ────────────────────────────────────────────────────────────────────────
+    private readonly PaperdollViewState _viewState = new();
+    private readonly List<UiItemList> _armorSlots = new();
+    private UiElement? _dollViewport;   // UiViewport wired in Slice 3; UiElement? keeps this task independent
+
     private PaperdollController(
         ImportedLayout layout, ClientObjectTable objects, Func<uint> playerGuid,
         Func<ItemType, uint, uint, uint, uint, uint> iconIds, Action<uint, uint>? sendWield,
@@ -80,6 +111,17 @@ public sealed class PaperdollController : IItemListDragHandler
         _objects.ObjectRemoved += OnObjectChanged;
         _objects.ObjectUpdated += OnObjectChanged;
 
+        // ── Slots-toggle wiring ───────────────────────────────────────────────────────────────────
+        foreach (var id in ArmorSlotElementIds)
+            if (layout.FindElement(id) is UiItemList armor) _armorSlots.Add(armor);
+
+        _dollViewport = layout.FindElement(0x100001D5u);   // doll viewport (may be null until Slice 3)
+
+        if (layout.FindElement(0x100005BEu) is UiButton slotsBtn)
+            slotsBtn.OnClick = () => { _viewState.Toggle(); ApplyView(); };
+
+        ApplyView();   // initial state = doll-view (armor slots hidden)
+
         Populate();
     }
 
@@ -161,6 +203,17 @@ public sealed class PaperdollController : IItemListDragHandler
         _sendWield?.Invoke(payload.ObjId, (uint)wieldMask);
     }
 
+    /// <summary>
+    /// Pushes the current <see cref="PaperdollViewState"/> onto the live widgets:
+    /// hides/shows the doll viewport and each armor slot according to the toggle.
+    /// Called once at construction (doll-view default) and on every button click.
+    /// </summary>
+    private void ApplyView()
+    {
+        if (_dollViewport is not null) _dollViewport.Visible = _viewState.DollVisible;
+        foreach (var a in _armorSlots) a.Visible = _viewState.ArmorSlotsVisible;
+    }
+
     /// <summary>Detach event handlers (idempotent).</summary>
     public void Dispose()
     {