feat: speed up admin clone import and enable Cache Components

- Clone import: defer FurnitureData.json writes and append all entries in a
  single batched write instead of one read-modify-write per item, removing
  the main serialization bottleneck for large batches.
- Clone import: raise SSE batch concurrency cap from 5 to 10 and bump the
  clone client/route default from 2 to 6.
- Add a flush hook to runSseBatch so callers can batch deferred work before
  batch_complete is emitted, and surface flush errors as an error event.
- Enable Next.js Cache Components (instant: false opt-out) and silence the
  related build warnings in next.config.ts.
- Switch isomorphic-dompurify to dompurify and refresh dependencies.

src/app/(site)/shop/page.tsx

@@ -9,7 +9,9 @@ import { db, WebsiteShopArticles, WebsiteShopCategories } from "@/lib/db";
 import { excerpt } from "@/lib/format";
 import { creditsPerUnit } from "@/lib/services/paypal";
 
-export const revalidate = 300;
+// TODO: Cache Components adoption. Refactor this route so this opt-out can be removed.
+// See: https://nextjs.org/docs/app/guides/migrating-to-cache-components
+export const instant = false;
 
 export const metadata = { title: "Shop" };
 

src/app/(site)/shop/topup/page.tsx

@@ -11,7 +11,9 @@ import {
 } from "@/lib/services/paypal";
 import TopUpForm from "./TopUpForm";
 
-export const dynamic = "force-dynamic";
+// TODO: Cache Components adoption. Refactor this route so this opt-out can be removed.
+// See: https://nextjs.org/docs/app/guides/migrating-to-cache-components
+export const instant = false;
 
 export default async function TopUpPage({
 	searchParams,