<ul><li><b>group.controller.php line 441 fix</b>: <code>htmlspecialchars_decode($data["rules_and_guidelines"])</code> — Deprecated warning when <code>rules_and_guidelines</code> is NULL in DB; PHP printed warning HTML before JSON output, breaking <code>JSON.parse(res)</code> in JS with <code>Unexpected token "<"</code>; added <code>?? ""</code> null coalescing</li><li>getGroupDetails now returns clean JSON for all groups ✓</li></ul>