845441b32c
Phase 1: Binary MQTT 3.1.1 wire protocol with PipeReader-based parsing, full packet type dispatch, and MQTT 3.1.1 compliance checks. Phase 2: Auth pipeline routing MQTT CONNECT through AuthService, TLS transport with SslStream wrapping, pinned cert validation. Phase 3: IMessageRouter refactor (NatsClient → INatsClient), MqttNatsClientAdapter for cross-protocol bridging, MqttTopicMapper with full Go-parity topic/subject translation. Phase 4: /connz mqtt_client field population, /varz actual MQTT port. Phase 5: JetStream persistence — MqttStreamInitializer creates 5 internal streams, MqttConsumerManager for QoS 1/2 consumers, subject-keyed session/retained lookups replacing linear scans. All 503 MQTT tests and 1589 Core tests pass.