Udp.open_local(port): a socket bound to 127.0.0.1 alone (udp.ll, udp_win.ll), for a port only this machine's tools reach - a dev link - where Udp.open binds every interface

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

runtime/native/namespaces.ludic

@@ -205,6 +205,7 @@ namespace Http {
 }
 namespace Udp {
   alias open(port) = udp_open
+  alias open_local(port) = udp_open_local
   alias port(socket) = udp_port
   alias send(socket, ip, port, bytes, len) = udp_send
   alias recv(socket, bytes, cap) = udp_recv