auto_socket.c: create_iface_tcp_socket returns stcp_server* instead of int,
ifa->v4_tcp/ifa->v6_tcp now properly track the created server, preventing
duplicate bind/listen on every reconcile_iface call.
etcp_connections.c: tcp_socket_add now resolves interface_addr via
get_interface_ip_by_index/get_interface_ipv6_addr_nl for any type (not just
PUBLIC), preventing NAT TCP v4 sockets from being destroyed due to INADDR_ANY.