feat(core): D.2b-B B-Wire — ClientObjectTable.UpsertProperties (create-if-absent)

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

tests/AcDream.Core.Tests/Items/ClientObjectTableUpdateTests.cs

@@ -0,0 +1,41 @@
+using AcDream.Core.Items;
+using Xunit;
+
+namespace AcDream.Core.Tests.Items;
+
+public sealed class ClientObjectTableUpdateTests
+{
+    [Fact]
+    public void UpsertProperties_unknownObject_createsThenMerges()
+    {
+        var t = new ClientObjectTable();
+        bool added = false;
+        t.ObjectAdded += _ => added = true;
+
+        var bundle = new PropertyBundle();
+        bundle.Ints[5] = 1234;     // EncumbranceVal
+
+        t.UpsertProperties(0x50000001u, bundle);
+
+        var o = t.Get(0x50000001u);
+        Assert.NotNull(o);
+        Assert.Equal(1234, o!.Properties.Ints[5]);
+        Assert.True(added);
+    }
+
+    [Fact]
+    public void UpsertProperties_existingObject_mergesAndFiresUpdated()
+    {
+        var t = new ClientObjectTable();
+        t.AddOrUpdate(new ClientObject { ObjectId = 0x50000001u });
+        bool updated = false;
+        t.ObjectUpdated += _ => updated = true;
+
+        var bundle = new PropertyBundle();
+        bundle.Ints[5] = 99;
+        t.UpsertProperties(0x50000001u, bundle);
+
+        Assert.Equal(99, t.Get(0x50000001u)!.Properties.Ints[5]);
+        Assert.True(updated);
+    }
+}