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>

assets/js/ticket.js

@@ -1528,7 +1528,7 @@ function submitReply(parentCommentId) {
                         <div class="comment-text" id="comment-text-${data.comment_id}" ${isMarkdownEnabled ? 'data-markdown' : ''}>
                             ${displayText}
                         </div>
-                        <textarea class="comment-edit-raw" id="comment-raw-${data.comment_id}" style="display:none;">${commentText.replace(/</g, '&lt;').replace(/>/g, '&gt;')}</textarea>
+                        <textarea class="comment-edit-raw is-hidden" id="comment-raw-${data.comment_id}">${commentText.replace(/</g, '&lt;').replace(/>/g, '&gt;')}</textarea>
                     </div>
                 `;