feat(items): port retail shared cooldown overlays

Preserve public shared-cooldown metadata, resolve the authoritative cooldown enchantment with retail expiry semantics, and project the exact ten DAT-authored radial steps through the shared retained item-slot architecture.

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

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

@@ -92,4 +92,27 @@ public class ItemListCellTemplateTests
         // m_elem_Icon ItemSlot_Empty state is the brown/gold 0x06001A97 surface.
         Assert.Equal(0x06001A97u, sprite);
     }
+
+    [Fact]
+    public void Shared_UIItem_resolves_all_ten_cooldown_overlays()
+    {
+        var datDir = DatDir();
+        if (datDir is null) return;
+
+        using var dats = new DatCollection(datDir, DatAccessType.Read);
+        ItemCooldownAssets? assets = ItemCooldownAssets.TryLoad(dats);
+
+        Assert.NotNull(assets);
+        Assert.Equal(ItemCooldownAssets.OverlayCount, assets.Value.Sprites.Count);
+        Assert.Equal(
+            new uint[]
+            {
+                0x060067CFu, 0x060067D0u, 0x060067D1u, 0x060067D2u, 0x060067D3u,
+                0x060067D4u, 0x060067D5u, 0x060067D6u, 0x060067D7u, 0x060067D8u,
+            },
+            assets.Value.Sprites);
+        _out.WriteLine(
+            string.Join(", ", assets.Value.Sprites.Select(id => $"0x{id:X8}")));
+    }
+
 }