feat(net): D.2b-B B-Wire — ParseViewContents (0x0196)

GameEvents.ParseViewContents parses the ViewContents GameEvent payload:
containerGuid + count + [guid, containerType]×count. Records
ViewContentsEntry and ViewContents added. 3 unit tests added in
GameEventsInventoryTests.cs (two-entry, zero-count, truncated).

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

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

@@ -0,0 +1,45 @@
+using System.Buffers.Binary;
+using AcDream.Core.Net.Messages;
+using Xunit;
+
+namespace AcDream.Core.Net.Tests.Messages;
+
+public sealed class GameEventsInventoryTests
+{
+    [Fact]
+    public void ParseViewContents_twoEntries_returnsContainerAndItems()
+    {
+        // containerGuid + count(2) + 2×{guid, containerType}
+        var b = new byte[4 + 4 + 2 * 8];
+        BinaryPrimitives.WriteUInt32LittleEndian(b.AsSpan(0), 0x500000C9u); // containerGuid
+        BinaryPrimitives.WriteUInt32LittleEndian(b.AsSpan(4), 2u);          // count
+        BinaryPrimitives.WriteUInt32LittleEndian(b.AsSpan(8), 0x50000A01u); // guid 1
+        BinaryPrimitives.WriteUInt32LittleEndian(b.AsSpan(12), 0u);         // type 1 (item)
+        BinaryPrimitives.WriteUInt32LittleEndian(b.AsSpan(16), 0x50000A02u);// guid 2
+        BinaryPrimitives.WriteUInt32LittleEndian(b.AsSpan(20), 1u);         // type 2 (container)
+
+        var p = GameEvents.ParseViewContents(b);
+        Assert.NotNull(p);
+        Assert.Equal(0x500000C9u, p!.Value.ContainerGuid);
+        Assert.Equal(2, p.Value.Items.Count);
+        Assert.Equal(0x50000A01u, p.Value.Items[0].Guid);
+        Assert.Equal(0u, p.Value.Items[0].ContainerType);
+        Assert.Equal(0x50000A02u, p.Value.Items[1].Guid);
+        Assert.Equal(1u, p.Value.Items[1].ContainerType);
+    }
+
+    [Fact]
+    public void ParseViewContents_zeroCount_returnsEmptyList()
+    {
+        var b = new byte[8];
+        BinaryPrimitives.WriteUInt32LittleEndian(b.AsSpan(0), 0x500000C9u);
+        BinaryPrimitives.WriteUInt32LittleEndian(b.AsSpan(4), 0u);
+        var p = GameEvents.ParseViewContents(b);
+        Assert.NotNull(p);
+        Assert.Empty(p!.Value.Items);
+    }
+
+    [Fact]
+    public void ParseViewContents_truncated_returnsNull()
+        => Assert.Null(GameEvents.ParseViewContents(new byte[4]));
+}