Fix: Treat a zero MaxBufferedBytes as disabled

Consistent with the per-IP limits, a zero cap now means "no limit" instead
of closing every connection after its first byte, so a Config built from
zero values cannot wedge the listener.

Co-Authored-By: deepseek-v4-pro

server/go/server/server.go

@@ -412,7 +412,7 @@ func (s *Server) handleConnection(conn net.Conn) {
 			// Hard cap on unparsed inbound bytes (memory-DoS guard). A peer
 			// that sends bytes that never assemble into a complete packet can
 			// otherwise grow this buffer without bound.
-			if ctx.InBuffer.Len() > s.config.MaxBufferedBytes {
+			if s.config.MaxBufferedBytes > 0 && ctx.InBuffer.Len() > s.config.MaxBufferedBytes {
 				s.logger.Warn("Inbound buffer exceeded %d bytes from ip=%s conn=%d — closing",
 					s.config.MaxBufferedBytes, ctx.GetPeerIP(), ctx.ID)
 				break