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/lib/cache.test.ts

@@ -0,0 +1,65 @@
+import { describe, expect, it, vi } from "vitest";
+
+vi.mock("@/lib/redis", () => ({
+	redis: null,
+}));
+
+import { cached, invalidateMemory } from "./cache";
+
+describe("cached (memory-only, no Redis)", () => {
+	it("computes once and serves the cached value", async () => {
+		const fn = vi.fn(async () => 42);
+		const key = `once-${Math.random()}`;
+		expect(await cached(key, 10_000, fn)).toBe(42);
+		expect(await cached(key, 10_000, fn)).toBe(42);
+		expect(fn).toHaveBeenCalledTimes(1);
+	});
+
+	it("dedupes concurrent misses into a single computation", async () => {
+		let resolveFn: (value: number) => void = () => {};
+		const fn = vi.fn(
+			() =>
+				new Promise<number>((resolve) => {
+					resolveFn = resolve;
+				}),
+		);
+		const key = `dedupe-${Math.random()}`;
+		const p1 = cached(key, 10_000, fn);
+		const p2 = cached(key, 10_000, fn);
+		const p3 = cached(key, 10_000, fn);
+		resolveFn(7);
+		expect(await Promise.all([p1, p2, p3])).toEqual([7, 7, 7]);
+		expect(fn).toHaveBeenCalledTimes(1);
+	});
+
+	it("recomputes after the TTL expires", async () => {
+		let count = 0;
+		const fn = vi.fn(async () => ++count);
+		const key = `ttl-${Math.random()}`;
+		expect(await cached(key, 1, fn)).toBe(1);
+		expect(await cached(key, 1, fn)).toBe(1);
+		await new Promise((r) => setTimeout(r, 10));
+		expect(await cached(key, 1, fn)).toBe(2);
+		expect(fn).toHaveBeenCalledTimes(2);
+	});
+
+	it("invalidates a key so the next read recomputes", async () => {
+		let count = 0;
+		const fn = vi.fn(async () => ++count);
+		const key = `inv-${Math.random()}`;
+		expect(await cached(key, 10_000, fn)).toBe(1);
+		invalidateMemory(key);
+		expect(await cached(key, 10_000, fn)).toBe(2);
+		expect(fn).toHaveBeenCalledTimes(2);
+	});
+
+	it("evicts the oldest entry when the in-memory cache is full", async () => {
+		const fn = vi.fn(async () => 1);
+		for (let i = 0; i < 600; i++) {
+			await cached(`bulk-${i}`, 10_000, fn);
+		}
+		// Key "bulk-0" was evicted (insertion order), so it must recompute.
+		await cached("bulk-0", 10_000, fn);
+		expect(fn).toHaveBeenCalledTimes(601);
+	});
+});