Sub-ticket of MSG-248 EPIC: cdw+hub seam optimization (Elazar 2026-07-02 via coder-chatduo-cc, 4-agent: coder-chatduo, coder-llmmsgsrv, pm-llmmsgsrv, nw-venus) - collapse cdw->hub loopback chatter + delivery latency, from MSG-237 audit · llmmsg-srv