fix(anim): Phase L.1c route creature actions and despawns

Handle retail ObjectDelete (0xF747) using CM_Physics::DispatchSB_DeleteObject 0x006AC6A0 / SmartBox::HandleDeleteObject 0x00451EA0 and ACE GameMessageDeleteObject so dead creatures are removed when corpses spawn.

Route action-class ForwardCommand values through AnimationCommandRouter/PlayAction instead of SetCycle so creature attack commands 0x51/0x52/0x53 survive the immediate Ready echo, matching CMotionTable::GetObjectSequence 0x00522860 / ACE MotionTable.GetObjectSequence.

Use server-authoritative UpdatePosition velocity, or observed server position delta for non-player entities when HasVelocity is absent, to reduce monster/NPC chase lag without applying player RUM prediction to server-controlled creatures.

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

@@ -0,0 +1,39 @@
+using System.Buffers.Binary;
+using AcDream.Core.Net.Messages;
+using Xunit;
+
+namespace AcDream.Core.Net.Tests.Messages;
+
+public sealed class DeleteObjectTests
+{
+    [Fact]
+    public void RejectsWrongOpcode()
+    {
+        Span<byte> body = stackalloc byte[12];
+        BinaryPrimitives.WriteUInt32LittleEndian(body, 0xDEADBEEFu);
+
+        Assert.Null(DeleteObject.TryParse(body));
+    }
+
+    [Fact]
+    public void RejectsTruncated()
+    {
+        Assert.Null(DeleteObject.TryParse(ReadOnlySpan<byte>.Empty));
+        Assert.Null(DeleteObject.TryParse(new byte[9]));
+    }
+
+    [Fact]
+    public void ParsesGuidAndInstanceSequence()
+    {
+        Span<byte> body = stackalloc byte[12];
+        BinaryPrimitives.WriteUInt32LittleEndian(body, DeleteObject.Opcode);
+        BinaryPrimitives.WriteUInt32LittleEndian(body.Slice(4), 0x80000439u);
+        BinaryPrimitives.WriteUInt16LittleEndian(body.Slice(8), 0x1234);
+
+        var parsed = DeleteObject.TryParse(body);
+
+        Assert.NotNull(parsed);
+        Assert.Equal(0x80000439u, parsed!.Value.Guid);
+        Assert.Equal((ushort)0x1234, parsed.Value.InstanceSequence);
+    }
+}