fix: AuthProvider en layout raíz (login usaba contexto vacío y no hacía nada)

frontend/src/app/(app)/layout.tsx

@@ -1,7 +1,7 @@
 "use client";
 
 import { useState } from "react";
-import { AuthProvider, useAuth } from "@/lib/auth";
+import { useAuth } from "@/lib/auth";
 import Sidebar from "@/components/Sidebar";
 import { useRouter } from "next/navigation";
 import { useEffect } from "react";
@@ -98,9 +98,5 @@ function TopNavbarUser() {
 }
 
 export default function AppLayout({ children }: { children: React.ReactNode }) {
-  return (
-    <AuthProvider>
-      <AppShell>{children}</AppShell>
-    </AuthProvider>
-  );
+  return <AppShell>{children}</AppShell>;
 }