Add performance optimizations and component refactors

- Cache read-heavy public API routes via redisCache (leaderboard, values,
  shop, articles, photos, guilds, teams, staff, users, home, radio, badges)
- Add single-flight and bounded-memory cache layer with unit tests
- Parallelize independent DB queries on search, rares, shop, staff, polls
  and profile pages
- Push radio points leaderboard aggregation to SQL with a LIMIT
- Split studio-client and import-furni-client into focused modules
- Clean up next.config.ts

src/components/admin/studio/checkbox-dot.tsx

@@ -0,0 +1,22 @@
+"use client";
+
+import { Check } from "lucide-react";
+
+import { cn } from "@/lib/utils";
+
+export function CheckboxDot({ checked }: { checked: boolean }) {
+	return (
+		<span
+			className={cn(
+				"grid h-3.5 w-3.5 place-items-center rounded border transition-colors",
+				checked
+					? "border-[var(--admin-accent)] bg-[var(--admin-accent)]"
+					: "border-[var(--admin-border)] bg-transparent",
+			)}
+		>
+			{checked ? (
+				<Check size={10} className="text-[var(--admin-accent-foreground)]" />
+			) : null}
+		</span>
+	);
+}