fix: various inline style cleanup, a11y improvements, and bind_param bug

- Replace style="text-align:center" with .lt-text-center utility class in
  WorkflowDesignerView, CustomFieldsView, error_403, error_404, DashboardView JS string
- Replace style="margin-top:..." with .lt-mt-sm utility in WorkflowDesignerView
- Switch comment-edit-raw data-store textareas to .is-hidden class (TicketView PHP
  + JS-rendered; ticket.js template literal) — these are never shown, only read via .value
- Add aria-describedby="visibilityGroupsHint" + id on hint <p> in CreateTicketView
- Fix bind_param type string bug in manage_workflows.php PUT handler: 'ssiiiii' → 'ssiiii'
  (7 type chars for 6 params caused binding error on workflow transition updates)

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

views/TicketView.php

@@ -596,9 +596,8 @@ $progressClass  = $slaBreached ? 'lt-progress--red' : ($slaPct >= 75 ? 'lt-progr
                         ? htmlspecialchars($comment['comment_text'])
                         : nl2br(htmlspecialchars($comment['comment_text'])) ?>
                   </div>
-                  <textarea class="lt-input lt-textarea comment-edit-raw"
+                  <textarea class="lt-input lt-textarea comment-edit-raw is-hidden"
                             id="comment-raw-<?= $commentId ?>"
-                            style="display:none"
                             aria-hidden="true"><?= htmlspecialchars($comment['comment_text']) ?></textarea>
                 </div>
                 <?php if (!empty($comment['replies'])): ?>
@@ -1263,7 +1262,7 @@ document.addEventListener('DOMContentLoaded', function () {
               '<div class="comment-text" id="comment-text-' + commentId + '"' + (mdEnabled ? ' data-markdown data-rendered="1"' : '') + '>' +
                 commentText +
               '</div>' +
-              '<textarea class="lt-input lt-textarea comment-edit-raw" id="comment-raw-' + commentId + '" style="display:none" aria-hidden="true">' +
+              '<textarea class="lt-input lt-textarea comment-edit-raw is-hidden" id="comment-raw-' + commentId + '" aria-hidden="true">' +
                 escapedRaw +
               '</textarea>' +
             '</div>';