Fix session expiration handling

frontend/src/pages/auth/LoginPage.jsx

@@ -1,12 +1,14 @@
-import { useMemo, useState } from 'react';
-import { useNavigate, Link } from 'react-router-dom';
+import { useEffect, useMemo, useState } from 'react';
+import { useNavigate, Link, useSearchParams } from 'react-router-dom';
 import { useAuth } from '../../contexts/AuthContext';
 import { Download, PenTool } from 'lucide-react';
 import toast from 'react-hot-toast';
+import { SESSION_EXPIRED_MESSAGE, translateApiError } from '../../utils/session';
 
 export default function LoginPage() {
   const { login } = useAuth();
   const navigate = useNavigate();
+  const [searchParams, setSearchParams] = useSearchParams();
   const [form, setForm] = useState({ email: '', password: '' });
   const [loading, setLoading] = useState(false);
   const apiBaseUrl = (import.meta.env.VITE_API_URL || 'http://localhost:4000').replace(/\/$/, '');
@@ -16,6 +18,13 @@ export default function LoginPage() {
     return /Android/i.test(navigator.userAgent || '');
   }, []);
 
+  useEffect(() => {
+    if (searchParams.get('sessionExpired') === '1') {
+      toast.error(SESSION_EXPIRED_MESSAGE);
+      setSearchParams({}, { replace: true });
+    }
+  }, [searchParams, setSearchParams]);
+
   const handleChange = (e) => setForm((f) => ({ ...f, [e.target.name]: e.target.value }));
 
   const handleSubmit = async (e) => {
@@ -26,7 +35,7 @@ export default function LoginPage() {
       navigate('/dashboard');
     } catch (err) {
       const code = err.response?.data?.code;
-      const message = err.response?.data?.error || 'Error al iniciar sesión';
+      const message = translateApiError(err, 'Error al iniciar sesión');
 
       if (code === 'EMAIL_NOT_VERIFIED') {
         toast.success('Tu cuenta aún no está validada. Te enviamos un nuevo correo de confirmación.');

frontend/src/pages/auth/RegisterPage.jsx

@@ -5,6 +5,7 @@ import { CheckSquare, FileCheck2, FileText, PenTool, ShieldCheck, Tag, X } from
 import { Document, Page, pdfjs } from 'react-pdf';
 import { getLegalTemplatePreview, getLegalTemplates } from '../../api/public';
 import toast from 'react-hot-toast';
+import { translateApiError } from '../../utils/session';
 
 import 'react-pdf/dist/Page/AnnotationLayer.css';
 import 'react-pdf/dist/Page/TextLayer.css';
@@ -149,7 +150,7 @@ export default function RegisterPage() {
       toast.success('Cuenta creada. Revisa tu correo para confirmar tu usuario y recibir los documentos legales firmados.');
       navigate('/login');
     } catch (err) {
-      toast.error(err.response?.data?.error || 'Error al registrarse');
+      toast.error(translateApiError(err, 'Error al registrarse'));
     } finally {
       setLoading(false);
     }