<h4>Authentication System Updates</h4><ul><li>Updated all OAuth provider paths to use <code>BASEPATH_</code> constant</li><li>Applied conditional <code>session_start()</code> across all authentication includes</li><li>Updated <code>$config['base_path']</code> to use dynamic <code>BASEPATH_</code></li><li>Protected SESSION array access with null coalescing in login, redirect, and OAuth flows</li><li>Added CSRF token validation (<code>$globalclass-&gt;csrf_token()</code>) across all controllers</li></ul>