Function start_network_disabled 

pub fn start_network_disabled() -> NetworkHandle

huddle 0.8: build a NetworkHandle with no libp2p swarm — the onion-relay-only (NetworkMode::Server) path. We still hand back a fully-functional handle so the rest of the app is oblivious: room subscribe/unsubscribe/publish mirror to the attached ServerClient exactly as before, while the libp2p-specific commands (dial, announce, accept/reject, …) are simply drained and dropped. A tiny task consumes cmd_rx so the bounded channel never fills and send().await never blocks; it exits on Shutdown.