fix: RecurringTicketModel INSERT bind_param type string mismatch

next_run_at was typed 'i' (int) but stores a datetime string → should be 's'.
is_active was typed 's' (string) but stores 0/1 boolean → should be 'i'.
Positions 10-11 were swapped: 'ssssiiisssis' → 'ssssiiisssii'.
The UPDATE method already had the correct types; only INSERT was affected.

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

models/RecurringTicketModel.php

@@ -58,7 +58,7 @@ class RecurringTicketModel {
                 VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)";
 
         $stmt = $this->conn->prepare($sql);
-        $stmt->bind_param('ssssiiisssis',
+        $stmt->bind_param('ssssiiisssii',
             $data['title_template'],
             $data['description_template'],
             $data['category'],