You can do this either in the view app/views/admin/default/admin_main.pdt or in the controller app/controllers/admin_main.php. In the view you would change:
if (!empty($quicklinks)) {
To something like this
$quicklinks = array_merge([(object)['uri' => 'https://yourwordpress.com', 'title' => 'WordPress Calendar']], (isset($quicklinks) ? $quicklinks : []));
if (!empty($quicklinks)) {
OR in the controller you could change:
$this->set(
'quicklinks',
$this->Staff->getQuickLinks($this->Session->read('blesta_staff_id'), $this->company_id)
);
To something like this:
$this->set(
'quicklinks',
array_merge(
[(object)['uri' => 'https://yourwordpress.com', 'title' => 'WordPress Calendar']],
$this->Staff->getQuickLinks($this->Session->read('blesta_staff_id'), $this->company_id)
)
);