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/api/badges/leaderboard/route.ts

@@ -1,12 +1,11 @@
 import { eq, sql } from "drizzle-orm";
+import { connection } from "next/server";
 import { apiJson } from "@/lib/api";
 import { bearerUserId } from "@/lib/api-auth";
 import { auth } from "@/lib/auth";
 import { db, User, UsersSettings } from "@/lib/db";
 import { logger } from "@/lib/logger";
 
-export const dynamic = "force-dynamic";
-
 type BadgeRarityKey =
 	| "common"
 	| "rare"
@@ -301,6 +300,7 @@ async function loadRarityBoard(
 }
 
 export async function GET(req: Request) {
+	await connection();
 	try {
 		let userId: number | null = await bearerUserId(req);
 		if (!userId) {