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/admin/WorkflowDesignerView.php

@@ -31,13 +31,13 @@ include __DIR__ . '/../../views/layout_header.php';
           $toCount = 0;
           if (isset($workflows)) { foreach ($workflows as $w) { if ($w['from_status'] === $status) $toCount++; } }
       ?>
-        <div class="lt-card" style="text-align:center">
+        <div class="lt-card lt-text-center">
           <span class="lt-status lt-status-<?= $slug ?>"><?= $status ?></span>
           <div class="lt-text-xs lt-text-muted lt-mt-sm">→ <?= $toCount ?> transition<?= $toCount !== 1 ? 's' : '' ?></div>
         </div>
       <?php endforeach ?>
     </div>
-    <p class="lt-text-xs lt-text-muted" style="margin-top:0.5rem">
+    <p class="lt-text-xs lt-text-muted lt-mt-sm">
       Define which status transitions are allowed. This controls what options appear in the status dropdown on tickets.
     </p>
   </div>
@@ -69,17 +69,17 @@ include __DIR__ . '/../../views/layout_header.php';
               <td data-label="From">
                 <span class="lt-status lt-status-<?= $fromSlug ?>"><?= htmlspecialchars($wf['from_status']) ?></span>
               </td>
-              <td class="lt-text-amber lt-text-xs" style="text-align:center">&rarr;</td>
+              <td class="lt-text-amber lt-text-xs lt-text-center">&rarr;</td>
               <td data-label="To">
                 <span class="lt-status lt-status-<?= $toSlug ?>"><?= htmlspecialchars($wf['to_status']) ?></span>
               </td>
-              <td data-label="Req. Comment" style="text-align:center">
+              <td data-label="Req. Comment" class="lt-text-center">
                 <?= $wf['requires_comment'] ? '<span class="lt-text-cyan">✓</span>' : '<span class="lt-text-muted">—</span>' ?>
               </td>
-              <td data-label="Req. Admin" style="text-align:center">
+              <td data-label="Req. Admin" class="lt-text-center">
                 <?= $wf['requires_admin'] ? '<span class="lt-text-amber">✓</span>' : '<span class="lt-text-muted">—</span>' ?>
               </td>
-              <td data-label="Active" style="text-align:center">
+              <td data-label="Active" class="lt-text-center">
                 <?= $wf['is_active']
                     ? '<span class="lt-text-cyan">✓</span>'
                     : '<span class="lt-text-danger">✗</span>' ?>