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>

api/manage_workflows.php

@@ -79,6 +79,12 @@ try {
         case 'POST':
             $data = json_decode(file_get_contents('php://input'), true);
 
+            if (($data['from_status'] ?? '') === ($data['to_status'] ?? '')) {
+                http_response_code(400);
+                echo json_encode(['success' => false, 'error' => 'From Status and To Status cannot be the same']);
+                exit;
+            }
+
             $stmt = $conn->prepare("INSERT INTO status_transitions (from_status, to_status, requires_comment, requires_admin, is_active)
                                     VALUES (?, ?, ?, ?, ?)");
             $wf_from    = $data['from_status'];
@@ -116,6 +122,12 @@ try {
 
             $data = json_decode(file_get_contents('php://input'), true);
 
+            if (($data['from_status'] ?? '') === ($data['to_status'] ?? '')) {
+                http_response_code(400);
+                echo json_encode(['success' => false, 'error' => 'From Status and To Status cannot be the same']);
+                exit;
+            }
+
             $stmt = $conn->prepare("UPDATE status_transitions SET
                                     from_status = ?, to_status = ?, requires_comment = ?, requires_admin = ?, is_active = ?
                                     WHERE transition_id = ?");