feat(home): show convite necessário; route admin/guest tokens

app/page.tsx

@@ -1,6 +1,63 @@
 'use client';
 
-export default function Home() {
+import { useEffect, useState } from 'react';
+import { useRouter, useSearchParams } from 'next/navigation';
+import { authApi } from '@/lib/api';
+
+export default function HomePage() {
+  const router = useRouter();
+  const params = useSearchParams();
+  const [state, setState] = useState<'checking' | 'guest' | 'none'>('checking');
+  const [guestName, setGuestName] = useState<string>('');
+
+  useEffect(() => {
+    let cancelled = false;
+    (async () => {
+      const adm = params.get('adm');
+      const usr = params.get('usr');
+      try {
+        if (adm) {
+          await authApi.session({ adm });
+          router.replace('/admin');
+          return;
+        }
+        if (usr) {
+          await authApi.session({ usr });
+        }
+        const who = await authApi.whoami();
+        if (cancelled) return;
+        if (who.role === 'admin') {
+          router.replace('/admin');
+          return;
+        }
+        if (who.role === 'guest') {
+          setGuestName(who.guest.name);
+          setState('guest');
+          return;
+        }
+        setState('none');
+      } catch {
+        if (!cancelled) setState('none');
+      }
+    })();
+    return () => { cancelled = true; };
+  }, [params, router]);
+
+  if (state === 'checking') {
+    return <div className="min-h-screen flex items-center justify-center text-gray-500">Carregando…</div>;
+  }
+
+  if (state === 'guest') {
+    return (
+      <div className="min-h-screen flex items-center justify-center text-center px-6">
+        <div>
+          <h1 className="text-3xl font-bold mb-2">Olá, {guestName}!</h1>
+          <p className="text-gray-500">Visite o link da lista que você recebeu.</p>
+        </div>
+      </div>
+    );
+  }
+
   return (
     <div className="min-h-screen flex items-center justify-center text-center px-6">
       <div>