invite+clipboard+conn_mgr: sock_meta for alien nodes, clipboard fix, bg_ping fix

- chat_core_connect_from_invite: add TOPO_SOCKMETA4 (id=0, UNKNOWN, UNKNOWN)
  so cm_has_direct_ip/cm_start_phase_direct can match socket_id=0 addr
- conn_mgr: cm_bg_ping_timer_cb reads real addr from nq->node->v4_addrs
  instead of NULL; added cm_bg_ping_noop_cb per required etcp_send_ping_to_socket
- invitedialog: set both QClipboard::Clipboard and Selection on Linux/X11

tools/chatgui/src/invitedialog.cpp

@@ -26,7 +26,10 @@ InviteDialog::InviteDialog(const QString& link, QWidget* parent)
     auto *btnLayout = new QHBoxLayout();
     auto *copyBtn = new QPushButton("Скопировать", this);
     connect(copyBtn, &QPushButton::clicked, this, [this, linkEdit]() {
-        QApplication::clipboard()->setText(m_link);
+        QClipboard* cb = QApplication::clipboard();
+        cb->setText(m_link, QClipboard::Clipboard);
+        if (cb->supportsSelection())
+            cb->setText(m_link, QClipboard::Selection);
         linkEdit->setFocus();
     });
     btnLayout->addWidget(copyBtn);