CorrelationEngine gains an optional publish_fn hook fired once per unique
attacker IP. The profiler worker — sole caller of the engine today —
carries the bus physically, builds a thread-safe publisher, and wraps it
with the attacker.observed topic before handing it in.
Bus stays optional: if get_bus() fails or DECNET_BUS_ENABLED=false, the
engine runs publish_fn=None and the worker degrades to DB-only. Hook
failures log a warning and never break ingestion.