feat(D.5.1): faithful toolbar slot numbers 1-9 (SetShortcutNum digit sprites, peace/war)

Port of UIElement_UIItem::SetShortcutNum (acclient_2013_pseudo_c.txt:229465) and
gmToolbarUI::RecvNotice_SetCombatMode (196610-196621). The 9 top-row toolbar slots
show digit labels 1-9 at all times (even when empty — confirmed from the user''s
retail screenshot). The digit sprites are real 32x32 PFID_A8R8G8B8 RenderSurfaces
with glyphs baked into the top-left corner (rest alpha=0), drawn Alphablend over
the slot icon/empty sprite.

Digit DID arrays (peace: property 0x10000042, war: 0x10000043) are read at startup
from LayoutDesc 0x21000037 element 0x1000034A under composite 0x10000346 using the
same ArrayBaseProperty{DataIdBaseProperty} pattern as LayoutImporter.ReadState.
A cited-constant fallback (same confirmed dat ids) is used if the dat navigation
fails. The war glyph set (darker/golden glyphs) switches on any combat stance;
peace glyphs (lighter) restore on NonCombat — re-stamped by RestampShortcutNumbers()
called from both Populate() and SetCombatMode().

Changes:
- UiItemSlot: ShortcutNum/ShortcutPeace/PeaceDigits/WarDigits state; SetShortcutNum/
  ClearShortcutNum; OnDraw restructured (no early return) so digit draws after icon.
- ToolbarController: _peaceDigits/_warDigits/_peace fields; Bind() gains peaceDigits/
  warDigits optional params; RestampShortcutNumbers() helper; Populate() and
  SetCombatMode() both call RestampShortcutNumbers().
- GameWindow: reads digit arrays under _datLock from LayoutDesc 0x21000037, passes to
  Bind(); cited constants as fallback.
- Tests: 5 new UiItemSlotTests (SetShortcutNum/ClearShortcutNum state); 4 new
  ToolbarControllerTests (top-row/bottom-row labels, peace/war switch, array injection).

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

src/AcDream.App/UI/UiItemSlot.cs

@@ -37,6 +37,40 @@ public sealed class UiItemSlot : UiElement
 
     public void Clear() { ItemId = 0; IconTexture = 0; }
 
+    // ── Shortcut number (slot label) ─────────────────────────────────────────
+    // Port of UIElement_UIItem::SetShortcutNum (acclient_2013_pseudo_c.txt:229465).
+    // Retail draws the digit on the cell's ShortcutNum sub-element, picking the
+    // digit image from a DID-array property: 0x10000042 (peace) / 0x10000043 (war),
+    // indexed by slot position. Each digit is a 32×32 PFID_A8R8G8B8 RenderSurface
+    // with the digit baked into the top-left corner (rest alpha=0), drawn Alphablend.
+
+    /// <summary>Slot position in the shortcut bar (0-indexed). -1 = no number (retail
+    /// SetVisible(0) when edi < 0). Top row: 0..8 → digits 1..9. Bottom row: -1.</summary>
+    public int ShortcutNum { get; private set; } = -1;
+
+    /// <summary>True = draw peace digit set; false = war digit set.</summary>
+    public bool ShortcutPeace { get; private set; } = true;
+
+    /// <summary>Peace digit DID array. Index i → digit (i+1) sprite RenderSurface id.
+    /// Injected by the controller after reading LayoutDesc 0x21000037.</summary>
+    public uint[]? PeaceDigits { get; set; }
+
+    /// <summary>War digit DID array. Same layout as PeaceDigits.</summary>
+    public uint[]? WarDigits { get; set; }
+
+    /// <summary>Set the slot's shortcut position and combat stance so the correct digit
+    /// is drawn. Call with index 0..8 for the top row; pass peace=true for NonCombat.</summary>
+    public void SetShortcutNum(int index, bool peace)
+    {
+        ShortcutNum   = index;
+        ShortcutPeace = peace;
+    }
+
+    /// <summary>Clear the shortcut number label (hides the digit).</summary>
+    public void ClearShortcutNum() { ShortcutNum = -1; }
+
+    // ── Events / draw ─────────────────────────────────────────────────────────
+
     /// <summary>Invoked by <see cref="OnEvent"/> when a left-button-down lands on
     /// a bound slot. Wired by <c>ToolbarController</c> to the use-item callback.</summary>
     public Action? Clicked { get; set; }
@@ -50,16 +84,37 @@ public sealed class UiItemSlot : UiElement
 
     protected override void OnDraw(UiRenderContext ctx)
     {
+        // Draw the icon (filled slot) or the empty-slot border. Both paths fall
+        // through to the digit draw below, so the slot label shows on all top-row
+        // slots regardless of whether they hold an item (retail screenshot confirms
+        // numbers on empty slots).
         if (ItemId != 0 && IconTexture != 0)
         {
             ctx.DrawSprite(IconTexture, 0f, 0f, Width, Height, 0f, 0f, 1f, 1f, Vector4.One);
-            return;
         }
-        if (SpriteResolve is not null && EmptySprite != 0)
+        else if (SpriteResolve is not null && EmptySprite != 0)
         {
             var (tex, _, _) = SpriteResolve(EmptySprite);
             if (tex != 0)
                 ctx.DrawSprite(tex, 0f, 0f, Width, Height, 0f, 0f, 1f, 1f, Vector4.One);
         }
+
+        // Digit overlay: UIElement_UIItem::SetShortcutNum (acclient_2013_pseudo_c.txt:229465).
+        // Each digit image is corner-baked (glyph in top-left, rest alpha=0) so we
+        // draw it full-cell size and the transparent region is invisible. DrawMode=Alphablend.
+        if (ShortcutNum >= 0 && SpriteResolve is not null)
+        {
+            var arr = ShortcutPeace ? PeaceDigits : WarDigits;
+            if (arr is not null && ShortcutNum < arr.Length)
+            {
+                uint did = arr[ShortcutNum];
+                if (did != 0)
+                {
+                    var (tex, _, _) = SpriteResolve(did);
+                    if (tex != 0)
+                        ctx.DrawSprite(tex, 0f, 0f, Width, Height, 0f, 0f, 1f, 1f, Vector4.One);
+                }
+            }
+        }
     }
 }