feat(inventory): port retail item giving (#216)

Preserve SmartBox drag-release coordinates, route the picked 3-D target through the retail AttemptPlaceIn3D policy, and send authoritative GiveObject requests with the selected stack quantity. Honor PlayerDescription's player secure-trade option and document the remaining trade-system boundary.

Co-Authored-By: Codex <noreply@openai.com>

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

@@ -197,6 +197,20 @@ public static class PlayerDescriptionParser
         SpellLists8             = 0x00000400,
     }
 
+    /// <summary>
+    /// Character-option bits consumed by the client runtime. Values are the
+    /// verbatim retail <c>CharacterOption</c> enum from
+    /// <c>named-retail/acclient.h:3404</c>.
+    /// </summary>
+    [Flags]
+    public enum CharacterOptions1 : uint
+    {
+        None = 0,
+        AllowGive = 0x00000040,
+        DragItemOnPlayerOpensSecureTrade = 0x04000000,
+        Default = 0x50C4A54A,
+    }
+
     /// <summary>One inventory entry — a guid plus a ContainerType
     /// discriminator (0=NonContainer, 1=Container, 2=Foci). Holtburger
     /// <c>events.rs:143-168</c> validates <c>ContainerType &lt;= 2</c>