Constant DM_BUS_TOPIC 

pub const DM_BUS_TOPIC: &str = "x0x/dm/v1/bus";

Shared DM transport topic. Every gossip-DM-capable agent subscribes here. Recipients filter by envelope.recipient_agent_id; non- recipients re-broadcast (with time-windowed dedup) so the envelope floods the mesh even when individual nodes have sparse PlumTree trees. Payload stays confidential via ML-KEM-768 encryption — non-recipients can’t decrypt even though they see the envelope.