Covers -ERR infrastructure, MaxConnections enforcement, pedantic subject validation on PUB, and server-side PING keepalive.
10 tasks from scaffolding through integration tests, each with TDD steps, exact file paths, and complete code. Bottom-up order: SubList → Parser → Client → Server → Integration.
Design covers the minimal NATS server port: pub/sub with wildcards and queue groups over System.IO.Pipelines, targeting .NET 10.