feat(D.5.1): capture IconId in CreateObject.Parsed (was discarded at cs:516)

ReadPackedDwordOfKnownType at the old line 516 was throwing the icon dat
id away. Declare iconId before the try-block, assign it there, and pass
IconId: iconId in the Parsed initializer so downstream UI (action bar /
equipment panels) can read the 0x06xxxxxx dat id without a separate lookup.

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

src/AcDream.Core.Net/Messages/CreateObject.cs

@@ -127,6 +127,12 @@ public static class CreateObject
         // defaults (0.05f elasticity, 0.5f friction).
         float? Friction = null,
         float? Elasticity = null,
+        // D.5.1 (2026-06-16): icon dat id (0x06xxxxxx) from the WeenieHeader
+        // fixed prefix. Previously discarded at cs:516; surfaced so the action
+        // bar / equipment UI can display the correct icon sprite without a
+        // separate dat lookup. Zero means "not sent" (packed zero sentinel in
+        // ReadPackedDwordOfKnownType preserves 0 as-is).
+        uint IconId = 0,
         // 2026-05-15: optional WeenieHeader tail. The retail
         // `ITEM_USEABLE _useability` (acclient.h:6478) — gates whether the
         // R-key Use action does anything. <c>(Useability &amp; USEABLE_REMOTE
@@ -506,6 +512,7 @@ public static class CreateObject
             string? name = null;
             uint? itemType = null;
             uint weenieFlags = 0;
+            uint iconId = 0;
             if (body.Length - pos >= 4)
             {
                 weenieFlags = ReadU32(body, ref pos);
@@ -513,7 +520,7 @@ public static class CreateObject
                 {
                     name = ReadString16L(body, ref pos);
                     _ = ReadPackedDword(body, ref pos);  // WeenieClassId
-                    _ = ReadPackedDwordOfKnownType(body, ref pos, IconTypePrefix);
+                    iconId = ReadPackedDwordOfKnownType(body, ref pos, IconTypePrefix);
                     if (body.Length - pos >= 4)
                         itemType = ReadU32(body, ref pos);
                     if (body.Length - pos >= 4)
@@ -611,7 +618,8 @@ public static class CreateObject
                 instanceSeq, teleportSeq, serverControlSeq, forcePositionSeq,
                 physicsState, objectDescriptionFlags,
                 friction, elasticity,
-                useability, useRadius);
+                IconId: iconId,
+                Useability: useability, UseRadius: useRadius);
 
             // Local helper: if we ran out of fields past PhysicsData, still
             // return the useful prefix (guid/position/setup/animParts/textures/palettes/scale/motion).

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

@@ -156,6 +156,29 @@ public sealed class CreateObjectTests
         Assert.Equal(2.5f, parsed.Value.UseRadius!.Value, precision: 3);
     }
 
+    // -----------------------------------------------------------------------
+    // D.5.1 (2026-06-16): IconId was discarded at cs:516 — surface it so the
+    // action bar / equipment UI can read icon dat ids from spawn messages.
+    // -----------------------------------------------------------------------
+
+    [Fact]
+    public void TryParse_IconId_Surfaced()
+    {
+        // Icon dat id 0x06001234: the wire writer strips the 0x06000000 prefix
+        // before packing (WritePackedDwordOfKnownType strips it), so we write
+        // 0x1234 as the packed value and expect 0x06001234 back.
+        byte[] body = BuildMinimalCreateObjectWithWeenieHeader(
+            guid: 0x50000009u,
+            name: "SwordIcon",
+            itemType: (uint)ItemType.MeleeWeapon,
+            iconId: 0x1234u);
+
+        var parsed = CreateObject.TryParse(body);
+
+        Assert.NotNull(parsed);
+        Assert.Equal(0x06001234u, parsed!.Value.IconId);
+    }
+
     private static byte[] BuildMinimalCreateObjectWithWeenieHeader(
         uint guid,
         string name,
@@ -163,6 +186,7 @@ public sealed class CreateObjectTests
         uint physicsState = 0,
         uint objectDescriptionFlags = 0,
         uint weenieFlags = 0,
+        uint iconId = 0,
         uint? value = null,
         uint? useability = null,
         float? useRadius = null)
@@ -187,8 +211,8 @@ public sealed class CreateObjectTests
         // Fixed WeenieHeader prefix per ACE SerializeCreateObject.
         WriteU32(bytes, weenieFlags);    // weenieFlags
         WriteString16L(bytes, name);
-        WritePackedDword(bytes, 0x1234); // WeenieClassId
+        WritePackedDword(bytes, 0x1234);   // WeenieClassId
-        WritePackedDword(bytes, 0);      // IconId via known-type writer
+        WritePackedDword(bytes, iconId);   // IconId via known-type writer (prefix stripped by ACE writer)
         WriteU32(bytes, itemType);
         WriteU32(bytes, objectDescriptionFlags);
         Align4(bytes);