Reconcile BGP paths and advertise selected routes per neighbor

tests/test_node_snapshot.c

@@ -41,6 +41,7 @@ static void test_bgp(struct UTUN_INSTANCE* signer) {
     struct ETCP_CONN from = { .instance = &receiver, .peer_node_id = 7 };
     group.nodes = queue_new(receiver.ua, 16, 0, 8, "snapshot_bgp");
     struct TOPO_NODE* ni = record(signer, INT64_MAX - 7, "BGP", 1);
+    from.peer_node_id = ni->node_id; from.links_up = 1;
     struct TOPO_GROUP_NODE nq = {0};
     uint8_t packet[4096] = {0};
     int len = topo_node_serialize(ni, &nq, group.group_id, 0, packet + sizeof(struct TOPOMSG_HEADER), sizeof(packet) - sizeof(struct TOPOMSG_HEADER), 0);