fix(remoteingress-core): disable Nagle's algorithm on edge, hub, and upstream TCP sockets to reduce control-frame latency

rust/crates/remoteingress-core/src/hub.rs

@@ -298,6 +298,8 @@ async fn handle_edge_connection(
     edge_token: CancellationToken,
     peer_addr: String,
 ) -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+    // Disable Nagle's algorithm for low-latency control frames (PING/PONG, WINDOW_UPDATE)
+    stream.set_nodelay(true)?;
     let tls_stream = acceptor.accept(stream).await?;
     let (read_half, mut write_half) = tokio::io::split(tls_stream);
     let mut buf_reader = BufReader::new(read_half);
@@ -520,6 +522,7 @@ async fn handle_edge_connection(
                                             format!("connect to SmartProxy {}:{} timed out (10s)", target, dest_port).into()
                                         })??;
 
+                                        upstream.set_nodelay(true)?;
                                         upstream.write_all(proxy_header.as_bytes()).await?;
 
                                         let (mut up_read, mut up_write) =