feat(D.5.2): capture UiEffects from CreateObject weenie header

Previously, weenieFlags bit 0x80 (UiEffects) was read + discarded with
`pos += 4`. Now it is captured into `uiEffects` and surfaced as
`Parsed.UiEffects` — the sole wire path for the effect bitfield since
PropertyInt.UiEffects (18) has no [AssessmentProperty] and never appears
in appraise responses.

Test builder gains `uint uiEffects = 0` param; write line updated to use
it. Three new parse tests: UiEffects_Captured, UiEffectsThenIconOverlay
(cursor-arithmetic regression), and NoUiEffectsBit_LeavesUiEffectsZero.

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

tests/AcDream.Core.Net.Tests/Messages/CreateObjectTests.cs

@@ -332,6 +332,52 @@ public sealed class CreateObjectTests
         Assert.Equal(0x06004444u, parsed.Value.IconUnderlayId);
     }
 
+    // -----------------------------------------------------------------------
+    // D.5.2 (2026-06-17): UiEffects bitfield (weenieFlags bit 0x80) — captured
+    // instead of skipped. Drives the icon's effect-overlay recolor.
+    // -----------------------------------------------------------------------
+
+    [Fact]
+    public void TryParse_UiEffects_Captured()
+    {
+        // weenieFlags 0x80 = UiEffects; value 0x1 = Magical.
+        byte[] body = BuildMinimalCreateObjectWithWeenieHeader(
+            guid: 0x50000010u, name: "MagicWand", itemType: (uint)ItemType.Caster,
+            weenieFlags: 0x80u, uiEffects: 0x1u);
+
+        var parsed = CreateObject.TryParse(body);
+
+        Assert.NotNull(parsed);
+        Assert.Equal(0x1u, parsed!.Value.UiEffects);
+    }
+
+    [Fact]
+    public void TryParse_UiEffectsThenIconOverlay_BothCaptured()
+    {
+        // Verifies the cursor still reaches IconOverlay after reading (not skipping) UiEffects.
+        byte[] body = BuildMinimalCreateObjectWithWeenieHeader(
+            guid: 0x50000011u, name: "GlowSword", itemType: (uint)ItemType.MeleeWeapon,
+            weenieFlags: 0x80u | 0x40000000u, uiEffects: 0x4u, iconOverlayId: 0x1ABCu);
+
+        var parsed = CreateObject.TryParse(body);
+
+        Assert.NotNull(parsed);
+        Assert.Equal(0x4u, parsed!.Value.UiEffects);
+        Assert.Equal(0x06001ABCu, parsed.Value.IconOverlayId);
+    }
+
+    [Fact]
+    public void TryParse_NoUiEffectsBit_LeavesUiEffectsZero()
+    {
+        byte[] body = BuildMinimalCreateObjectWithWeenieHeader(
+            guid: 0x50000012u, name: "PlainRock", itemType: (uint)ItemType.Misc, weenieFlags: 0u);
+
+        var parsed = CreateObject.TryParse(body);
+
+        Assert.NotNull(parsed);
+        Assert.Equal(0u, parsed!.Value.UiEffects);
+    }
+
     private static byte[] BuildMinimalCreateObjectWithWeenieHeader(
         uint guid,
         string name,
@@ -341,6 +387,7 @@ public sealed class CreateObjectTests
         uint weenieFlags = 0,
         uint weenieFlags2 = 0,
         uint iconId = 0,
+        uint uiEffects = 0,
         uint? value = null,
         uint? useability = null,
         float? useRadius = null,
@@ -400,7 +447,7 @@ public sealed class CreateObjectTests
             bytes.AddRange(tmp.ToArray());
         }
         if ((weenieFlags & 0x00080000u) != 0) WriteU32(bytes, 0);  // TargetType u32
-        if ((weenieFlags & 0x00000080u) != 0) WriteU32(bytes, 0);  // UiEffects u32
+        if ((weenieFlags & 0x00000080u) != 0) WriteU32(bytes, uiEffects);  // UiEffects u32
         if ((weenieFlags & 0x00000200u) != 0) bytes.Add(0);        // CombatUse sbyte/1 byte
         if ((weenieFlags & 0x00000400u) != 0) WriteU16(bytes, structure ?? 0);  // Structure u16
         if ((weenieFlags & 0x00000800u) != 0) WriteU16(bytes, maxStructure ?? 0); // MaxStructure u16