fix: resolve broken lib/ require paths in admin and normalise modern-normalize to .min.css

public/admin/thanks.php

@@ -1,7 +1,7 @@
 <?php
 // Bootstrap application
 require_once __DIR__ . "/../../config/bootstrap.php";
-require_once __DIR__ . '/../../lib/AdminAuth.php';
+require_once __DIR__ . '/../../src/AdminAuth.php';
 
 // PHP-level auth guard (defence-in-depth behind nginx Basic Auth)
 AdminAuth::requireLogin();
@@ -11,7 +11,7 @@ ini_set('display_errors', 0);
 ini_set('log_errors', 1);
 ini_set('error_log', 'error.log');
 
-require __DIR__ . '/../../lib/Database.php';
+require_once __DIR__ . '/../../src/Database.php';
 
 // Security: Validate thesis ID parameter
 $thesisId = null;