refactor(app): move auth gating and metadata to server-first patterns

app/page.tsx

@@ -1,65 +1,33 @@
-"use client";
-
-import { authClient } from "@/lib/auth-client";
-import { useRouter } from "next/navigation";
 import Link from "next/link";
-import { useTranslations } from "next-intl";
-import { toast } from "@/lib/toast";
+import { redirect } from "next/navigation";
 
-export default function Home() {
-  const t = useTranslations('toasts');
-  const { data: session, isPending } = authClient.useSession();
-  const router = useRouter();
+import { isAuthenticated } from "@/lib/auth-server";
 
-  if (isPending) {
-    return (
-      <main className="flex min-h-screen items-center justify-center">
-        <p className="text-muted-foreground">Laden...</p>
-      </main>
-    );
+export default async function Home() {
+  const authenticated = await isAuthenticated();
+
+  if (authenticated) {
+    redirect("/dashboard");
   }
 
   return (
     <main className="flex min-h-screen flex-col items-center justify-center gap-6 p-4">
       <h1 className="text-4xl font-bold">🍋 LemonSpace</h1>
 
-      {session?.user ? (
-        <div className="flex flex-col items-center gap-4">
-          <p className="text-lg">
-            Willkommen, <span className="font-semibold">{session.user.name}</span>
-          </p>
-          <Link
-            href="/dashboard"
-            className="rounded-lg bg-primary px-6 py-3 text-primary-foreground hover:bg-primary/90"
-          >
-            Zum Dashboard
-          </Link>
-          <button
-            onClick={() => {
-              toast.info(t('auth.signedOut'));
-              void authClient.signOut().then(() => router.refresh());
-            }}
-            className="rounded-lg border border-border px-6 py-3 text-sm hover:bg-accent"
-          >
-            Abmelden
-          </button>
-        </div>
-      ) : (
-        <div className="flex gap-4">
-          <Link
-            href="/auth/sign-in"
-            className="rounded-lg bg-primary px-6 py-3 text-primary-foreground hover:bg-primary/90"
-          >
-            Anmelden
-          </Link>
-          <Link
-            href="/auth/sign-up"
-            className="rounded-lg border border-border px-6 py-3 hover:bg-accent"
-          >
-            Registrieren
-          </Link>
-        </div>
-      )}
+      <div className="flex gap-4">
+        <Link
+          href="/auth/sign-in"
+          className="rounded-lg bg-primary px-6 py-3 text-primary-foreground hover:bg-primary/90"
+        >
+          Anmelden
+        </Link>
+        <Link
+          href="/auth/sign-up"
+          className="rounded-lg border border-border px-6 py-3 hover:bg-accent"
+        >
+          Registrieren
+        </Link>
+      </div>
     </main>
   );
 }