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/admin/radio/api-keys/page.tsx

@@ -10,6 +10,10 @@ import { Button } from "@/components/ui/button";
 import { db, RadioApiKeys } from "@/lib/db";
 import { formatDate } from "@/lib/format-date";
 
+// 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: "Radio API Keys" };
 
 type ApiKey = {

src/app/admin/radio/autodj/page.tsx

@@ -11,6 +11,10 @@ import { Button } from "@/components/ui/button";
 import { db, RadioAutoDjPlaylist } from "@/lib/db";
 import { formatDate } from "@/lib/format-date";
 
+// 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: "Radio AutoDJ" };
 
 type Track = {

src/app/admin/radio/banners/page.tsx

@@ -11,6 +11,10 @@ import { Button } from "@/components/ui/button";
 import { db, RadioBanners } from "@/lib/db";
 import { formatDate } from "@/lib/format-date";
 
+// 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;
+
 type Banner = {
 	id: bigint;
 	userId: bigint;

src/app/admin/radio/embed/page.tsx

@@ -6,6 +6,10 @@ import { resolveHotelName } from "@/lib/hotel-name";
 import { siteSettings } from "@/lib/services/site-settings";
 import { EmbedSnippet } from "./embed-snippet";
 
+// 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: "Radio Embed" };
 
 export default async function AdminRadioEmbedPage() {

src/app/admin/radio/history/page.tsx

@@ -4,6 +4,10 @@ import { StatusCard } from "@/components/admin/dashboard";
 import { db, RadioHistory, User } from "@/lib/db";
 import { formatDate } from "@/lib/format-date";
 
+// 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;
+
 type History = {
 	id: bigint;
 	userId: bigint;

src/app/admin/radio/layout.tsx

@@ -1,6 +1,10 @@
 import { redirect } from "next/navigation";
 import { canAccess, getAdminContext, PERMS } from "@/lib/permissions";
 
+// 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 RadioAdminLayout({
 	children,
 }: {

src/app/admin/radio/moderation/page.tsx

@@ -6,6 +6,10 @@ import { Button } from "@/components/ui/button";
 import { db, RadioShouts } from "@/lib/db";
 import { formatDate } from "@/lib/format-date";
 
+// 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;
+
 type Shout = {
 	id: bigint;
 	userId: bigint;

src/app/admin/radio/monitoring/page.tsx

@@ -2,6 +2,10 @@ import { getTranslations } from "next-intl/server";
 import { DiagnosticRow, StatusCard } from "@/components/admin/dashboard";
 import { siteSettings } from "@/lib/services/site-settings";
 
+// 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: "Radio Monitoring" };
 
 const FETCH_TIMEOUT_MS = 4000;

src/app/admin/radio/page.tsx

@@ -6,6 +6,10 @@ import { Button } from "@/components/ui/button";
 import { db, RadioApplications, RadioSchedules, RadioShouts } from "@/lib/db";
 import { formatDate } from "@/lib/format-date";
 
+// 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;
+
 type Shout = {
 	id: bigint;
 	userId: bigint;

src/app/admin/radio/points/page.tsx

@@ -4,6 +4,10 @@ import { StatusCard } from "@/components/admin/dashboard";
 import { Button } from "@/components/ui/button";
 import { siteSettings } from "@/lib/services/site-settings";
 
+// 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: "Radio Points" };
 
 const DEFAULTS = {

src/app/admin/radio/ranks/page.tsx

@@ -9,6 +9,10 @@ import { StatusCard } from "@/components/admin/dashboard";
 import { Button } from "@/components/ui/button";
 import { db, RadioRanks } from "@/lib/db";
 
+// 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;
+
 type Rank = {
 	id: bigint;
 	name: string;

src/app/admin/radio/settings/page.tsx

@@ -7,6 +7,10 @@ import { StatusCard } from "@/components/admin/dashboard";
 import { Button } from "@/components/ui/button";
 import { db, WebsiteSetting } from "@/lib/db";
 
+// 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;
+
 type Field = { key: string; comment: string };
 type Group = { title: string; fields: Field[] };