feat(auth): keep remember tokens on session timeout

- add timeout-specific logout path without remember-token revocation

- reset session timers after remember-me auto login

- compact session policy wording in admin settings (DE/EN)

- extend auth tests for timeout/manual logout behavior

lib/Service/Auth/AuthService.php

@@ -268,6 +268,19 @@ class AuthService
         ]);
     }
 
+    public function logoutDueToSessionTimeout(): void
+    {
+        $actorUserId = (int) ($this->sessionUser()['id'] ?? 0);
+        $actorTenantId = $this->currentTenantIdFromSession();
+        $this->sessionStore->remove('session_started_at');
+        $this->sessionStore->remove('session_last_activity');
+        Auth::logout();
+        $this->recordAuthEvent('auth.session.timeout', 'success', [
+            'actor_user_id' => $actorUserId > 0 ? $actorUserId : null,
+            'actor_tenant_id' => $actorTenantId > 0 ? $actorTenantId : null,
+        ]);
+    }
+
     public function logoutAndRedirect(string $target = 'login'): void
     {
         $this->logout();