feat(admin): Server Action'larla kullanıcı yönetimi ve gerçek oturumlu sayfalar

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/app/(auth)/login/page.tsx

@@ -1,14 +1,27 @@
 import type { Metadata } from "next";
+import { redirect } from "next/navigation";
+import { Suspense } from "react";
 import { Logo } from "@/components/brand/logo";
 import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card";
 import { tr } from "@/i18n/tr";
+import { getCurrentUser } from "@/lib/dal";
 import { LoginForm } from "./login-form";
 
 export const metadata: Metadata = { title: tr.auth.loginTitle };
 
+/** Oturum açıksa dashboard'a yönlendirir (istek anında, Suspense içinde). */
+async function RedirectIfSignedIn() {
+  const user = await getCurrentUser();
+  if (user) redirect("/dashboard");
+  return null;
+}
+
 export default function LoginPage() {
   return (
     <main className="flex w-full max-w-sm flex-col items-center gap-6">
+      <Suspense fallback={null}>
+        <RedirectIfSignedIn />
+      </Suspense>
       <Logo priority className="scale-125" />
       <Card className="w-full">
         <CardHeader>