skapade registrering, logga in och logga ut. ändrade lite i auth.php

inc/php/auth.php

@@ -1,7 +1,23 @@
 <?php
 session_start();
+require_once($_SERVER['DOCUMENT_ROOT'] . '/db.php');
 
-if (!isset($_SESSION['user_id'])) {
+function isAuthenticated() {
+    if (!isset($_SESSION['user_id']) || !isset($_SESSION['uniqueid'])) {
+        return false;
+    }
+
+    $conn = getConnection();
+    $stmt = $conn->prepare("SELECT id FROM users WHERE id = :id AND uniqueid = :uniqueid");
+    $stmt->execute([
+        'id' => $_SESSION['user_id'],
+        'uniqueid' => $_SESSION['uniqueid'],
+    ]);
+
+    return $stmt->fetch() !== false;
+}
+
+if (!isAuthenticated()) {
     header("Location: /landing.php");
     exit();
 }