Guard lt.* calls when base.js unavailable to prevent crash

Wraps all lt.keys.initDefaults() calls in `if (window.lt)` guards across
6 view files. Adds `if (!window.lt) return` bail-out in keyboard-shortcuts.js
and `if (window.lt)` guard in settings.js DOMContentLoaded handler.

This prevents TypeError crashes when /web_template/base.js returns 404,
which was causing the admin menu click delegation to never register.

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

assets/js/keyboard-shortcuts.js

@@ -78,6 +78,8 @@ function showKeyboardHelp() {
 }
 
 document.addEventListener('DOMContentLoaded', function() {
+    if (!window.lt) return;
+
     // Ctrl+E: Toggle edit mode (ticket pages)
     lt.keys.on('ctrl+e', function() {
         const editButton = document.getElementById('editButton');