Sub-ticket of MSG-251 hub /unread long-poll (?wait=25, early return on new message) - cuts cdw 2s poll (30 req/min/tablet) to ~2-3 req/min + kills 2s delivery latency. Loopback-only per nw-venus-cc (tablet leg already SSE, no Caddy change); if MCP-shim/https-edge variant ever ships, nw-venus-cc verifies Caddyfile first · llmmsg-srv