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/devops/errors/page.tsx

@@ -5,6 +5,10 @@ import { Card, CardContent } from "@/components/ui/card";
 import { db, EmulatorErrors } from "@/lib/db";
 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 EmulatorErrorsPage({
 	searchParams,
 }: {

src/app/admin/devops/page.tsx

@@ -10,6 +10,10 @@ import { db, EmulatorErrors, EmulatorSettings } from "@/lib/db";
 import { canAccess, getAdminContext, PERMS } from "@/lib/permissions";
 import { HealthCheckClient } from "./health-check-client";
 
+// 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;
+
 async function getDevOpsData() {
 	const now = Math.floor(Date.now() / 1000);
 	const dayAgo = now - 86400;