feat: publish user completed payload to RabbitMQ

[gbzarelli]

Summary

• publish a dedicated RabbitMQ user-completed payload after successful enrichment and after the Kafka updated-event dispatch returns
• add a separate RabbitMQ output port, adapter, topology, and runtime configuration
• document the architectural split with ADR 0004 and cover the flow in unit and acceptance tests

Context

• Refs Publish user-completed integration payload to RabbitMQ after successful enrichment #6
• Stacked on top of fix: simplify Dockerfile Java 21 base #7 so the Dockerfile fix can merge independently first

Validation

• make run-all-tests