fix: cache CSRF token in View to prevent mismatch on multiple renders

src/Core/View.php

@@ -10,6 +10,7 @@ class View
     private string $layout = 'main';
     private array $data = [];
     private Security $security;
+    private ?string $csrfTokenCache = null;
 
     public function __construct(Security $security)
     {
@@ -80,7 +81,10 @@ class View
 
     public function csrfToken(): string
     {
-        return $this->security->generateCSRFToken();
+        if ($this->csrfTokenCache === null) {
+            $this->csrfTokenCache = $this->security->generateCSRFToken();
+        }
+        return $this->csrfTokenCache;
     }
 
     public function csrfField(): string