Add comment skeleton loaders, workflow validation, monthly schedule fix

- TicketView.php: Show 3 lt-skeleton-card placeholders in the comment list
  while "Load more" fetches; skeletons are removed on resolve or error
- ticket.css: Add .comment-skeleton margin spacing
- WorkflowDesignerView.php + manage_workflows.php: Prevent creating/editing
  status transitions where from_status === to_status (client + server check)
- RecurringTicketsView.php: Expand monthly day picker from 28 to 31 days
  (days 29-31 labelled "last day in short months")
- RecurringTicketModel.php: Clamp monthly schedule day to last day of target
  month using format('t') instead of hard-capping at 28

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

views/admin/WorkflowDesignerView.php

@@ -216,6 +216,10 @@ function saveTransition(e) {
         requires_admin:   document.getElementById('requires_admin').checked   ? 1 : 0,
         is_active:        document.getElementById('wf_is_active').checked     ? 1 : 0,
     };
+    if (data.from_status === data.to_status) {
+        lt.toast.error('From Status and To Status cannot be the same');
+        return;
+    }
     var url     = '/api/manage_workflows.php' + (data.transition_id ? '?id=' + data.transition_id : '');
     var apiCall = data.transition_id ? lt.api.put(url, data) : lt.api.post(url, data);
     apiCall.then(function (result) {