Add a third Kafka listener (EXTERNAL://0.0.0.0:9093) so that
2.0 standalone services on other servers (e.g. 192.168.1.10) can
connect to 1.0's Kafka at 192.168.1.111:9093.
Listeners now:
- PLAINTEXT (kafka:29092) - internal Docker network
- PLAINTEXT_HOST (localhost:9092) - host-local access
- EXTERNAL (192.168.1.111:9093) - LAN access for remote services
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>