feat: complete remaining jetstream parity implementation plan

tests/NATS.Server.Tests/JetStreamAccountInfoApiTests.cs

@@ -0,0 +1,17 @@
+using NATS.Server.JetStream;
+using NATS.Server.JetStream.Api;
+
+namespace NATS.Server.Tests;
+
+public class JetStreamAccountInfoApiTests
+{
+    [Fact]
+    public void Account_info_returns_jetstream_limits_and_usage_shape()
+    {
+        var router = new JetStreamApiRouter(new StreamManager(), new ConsumerManager());
+        var response = router.Route("$JS.API.INFO", "{}"u8);
+
+        response.AccountInfo.ShouldNotBeNull();
+        response.Error.ShouldBeNull();
+    }
+}