feat: implement bff layer

app/api/books/route.ts

@@ -1,7 +1,7 @@
 import { NextResponse } from "next/server";
-import { prisma } from "@/lib/db";
+import { getAllBooks } from "@/lib/api";
 
 export async function GET() {
-  const metas = await prisma.bookMeta.findMany();
-  return NextResponse.json(metas.map((m) => ({ book: m.book, ...m.data as Record<string, unknown> })));
+  const books = await getAllBooks();
+  return NextResponse.json(books);
 }