Fix layout regressions, nav drawer structure, and security issues

- base.css: add width:100%+min-width:0 to .lt-main so flex column body
  doesn't shrink content due to margin:0 auto from .lt-container
- layout_header.php: restructure mobile nav drawer to match web_template
  exactly (nav-drawer-links nav, direct <a> links, section div, no ul/li
  wrapper, overlay after drawer); fix lt-nav-overlay id mismatch with
  base.js; rename lt-header-username -> lt-header-user (matches CSS);
  add JSON_HEX_TAG to all inline json_encode calls (closes </script> XSS)
- base.css: add lt-kv-row/label/value aliases (display:contents pattern
  used in web_template v1.2 kv-grid); add lt-badge-sm variant
- Admin views: add missing .catch() on editField/editRecurring/loadUsers;
  add JSON_HEX_TAG to json_encode in TemplatesView/WorkflowDesignerView
- TicketView: add JSON_HEX_TAG to all ticket-data json_encode calls

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

views/admin/TemplatesView.php

@@ -137,7 +137,7 @@ include __DIR__ . '/../../views/layout_header.php';
 </div>
 
 <script nonce="<?= $nonce ?>">
-var templates = <?= json_encode($templates ?? []) ?>;
+var templates = <?= json_encode($templates ?? [], JSON_HEX_TAG) ?>;
 
 document.addEventListener('click', function (e) {
     var target = e.target.closest('[data-action]');