feat(historian-gateway): scaffold Gateway driver project + consume client package

Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Historian.Gateway.Tests/ProjectSmokeTests.cs

@@ -0,0 +1,13 @@
+using Xunit;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.Historian.Gateway.Tests;
+
+public sealed class ProjectSmokeTests
+{
+    [Fact]
+    public void GatewayClientSeam_IsReferenceable()
+    {
+        var t = typeof(IHistorianGatewayClient);
+        Assert.Equal("IHistorianGatewayClient", t.Name);
+    }
+}