feat: complete final jetstream parity transport and runtime baselines

tests/NATS.Server.Tests/RouteRmsgForwardingTests.cs

@@ -0,0 +1,14 @@
+namespace NATS.Server.Tests;
+
+public class RouteRmsgForwardingTests
+{
+    [Fact]
+    public async Task Publish_on_serverA_reaches_remote_subscriber_on_serverB_via_RMSG()
+    {
+        await using var fx = await RouteFixture.StartTwoNodeClusterAsync();
+        await fx.SubscribeOnServerBAsync("foo.>");
+
+        await fx.PublishFromServerAAsync("foo.bar", "payload");
+        (await fx.ReadServerBMessageAsync()).ShouldContain("payload");
+    }
+}