feat(layout): login, uygulama kabuğu, alt menü, hızlı ekle ve dashboard

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

src/app/error.tsx

@@ -0,0 +1,27 @@
+"use client";
+
+import { useEffect } from "react";
+import { Button } from "@/components/ui/button";
+import { tr } from "@/i18n/tr";
+
+/** Rota hata sınırı. İç detay gösterilmez; yalnızca sunucu loglarıyla eşleşen hata kodu (digest). */
+export default function ErrorPage({ error, retry }: { error: unknown; retry: () => void }) {
+  useEffect(() => {
+    console.error(error);
+  }, [error]);
+
+  const digest = error instanceof Error && "digest" in error ? String(error.digest) : undefined;
+
+  return (
+    <main className="flex flex-1 flex-col items-center justify-center gap-4 p-8 text-center">
+      <h1 className="text-2xl font-semibold tracking-tight">{tr.errors.errorTitle}</h1>
+      <p className="max-w-md text-muted-foreground">{tr.errors.errorDescription}</p>
+      {digest ? (
+        <p className="text-xs text-muted-foreground">
+          {tr.errors.reference}: <code>{digest}</code>
+        </p>
+      ) : null}
+      <Button onClick={() => retry()}>{tr.errors.retry}</Button>
+    </main>
+  );
+}