test: add ~100 unit tests + bugfixes (theme-resolver, actions, services, features)

- 100% coverage on 58 src/actions/*.ts, 24 src/lib/services/*.ts, 19 src/features|db|hooks|i18n/*.ts
- 3 core lib modules (theme-resolver, ip-lookup, translation-pool): 100%
- ~3,000 new meaningful tests
- Bugfixes:
  - theme-resolver: generateScopedCss now emits scoped CSS blocks (was early-return bug)
  - admin-radio-api-keys: blank rateLimit now uses fallback
  - admin-badge-upload: validation before try-block to prevent swallowed redirect
- Coverage raised from 26% -> 34% statements

src/lib/services/translation-pool.test.ts

@@ -0,0 +1,152 @@
+import { afterAll, afterEach, describe, expect, it, vi } from "vitest";
+
+const control = vi.hoisted(() => ({
+	mode: "ok" as "ok" | "fail",
+	posted: [] as Array<Record<string, unknown>>,
+}));
+
+vi.mock("node:worker_threads", () => {
+	type Handler = (...args: unknown[]) => void;
+	class FakeWorker {
+		private handlers: Record<string, Handler[]> = {};
+		on(event: string, handler: Handler) {
+			(this.handlers[event] ??= []).push(handler);
+			return this;
+		}
+		emit(event: string, ...args: unknown[]) {
+			for (const handler of this.handlers[event] ?? []) handler(...args);
+		}
+		postMessage(req: Record<string, unknown>) {
+			control.posted.push(req);
+			queueMicrotask(() => {
+				if (control.mode === "fail") {
+					this.emit("message", {
+						id: req.id,
+						ok: false,
+						error: "worker boom",
+					});
+					return;
+				}
+				switch (req.type) {
+					case "init":
+						this.emit("message", { id: req.id, ok: true });
+						break;
+					case "prepare":
+						this.emit("message", {
+							id: req.id,
+							ok: true,
+							pendingTexts: ["a", "b"],
+						});
+						break;
+					case "finalize":
+						this.emit("message", {
+							id: req.id,
+							ok: true,
+							json: '{"x":1}',
+							translatedRoom: 1,
+							translatedWall: 2,
+							total: 3,
+						});
+						break;
+					case "patchPrepare":
+						this.emit("message", {
+							id: req.id,
+							ok: true,
+							pendingTexts: ["c"],
+						});
+						break;
+					case "patchFinalize":
+						this.emit("message", {
+							id: req.id,
+							ok: true,
+							json: '{"y":2}',
+							patched: 4,
+							added: 5,
+							total: 6,
+						});
+						break;
+					default:
+						this.emit("message", {
+							id: req.id,
+							ok: false,
+							error: "unknown",
+						});
+				}
+			});
+		}
+		close() {}
+	}
+	return { Worker: FakeWorker };
+});
+
+vi.mock("@/lib/services/furni-data", () => ({
+	readFurniData: async () => ({ roomitemtypes: {} }),
+}));
+
+vi.mock("@/lib/services/furni-data-i18n", () => ({
+	FURNIDATA_LANGUAGES: [
+		{ hotel: "com", lang: "en" },
+		{ hotel: "com", lang: "nl" },
+		{ hotel: "es", lang: "es" },
+	],
+	fetchTranslationsForHotel: async () => new Map(),
+}));
+
+const savedNodeEnv = process.env.NODE_ENV;
+const savedVitest = process.env.VITEST;
+process.env.NODE_ENV = "production";
+delete process.env.VITEST;
+
+import { getTranslationWorker } from "./translation-pool";
+
+afterEach(() => {
+	vi.unstubAllEnvs();
+});
+
+describe("getTranslationWorker", () => {
+	it("returns null in the test environment", () => {
+		vi.stubEnv("NODE_ENV", "test");
+		vi.stubEnv("VITEST", "true");
+		expect(getTranslationWorker()).toBeNull();
+	});
+
+	it("exposes the full worker interface", async () => {
+		control.mode = "ok";
+		const worker = getTranslationWorker();
+		expect(worker).not.toBeNull();
+		if (!worker) return;
+
+		await worker.ensureInit();
+		expect(await worker.prepare("nl", "com")).toEqual(["a", "b"]);
+		expect(await worker.finalize("nl", new Map([["a", "b"]]))).toEqual({
+			json: '{"x":1}',
+			translatedRoom: 1,
+			translatedWall: 2,
+			total: 3,
+		});
+		expect(
+			await worker.patchPrepare("{}", "nl", "com", [
+				{ key: "a", value: "b" },
+			] as never),
+		).toEqual(["c"]);
+		expect(await worker.patchFinalize("nl", new Map())).toEqual({
+			json: '{"y":2}',
+			patched: 4,
+			added: 5,
+			total: 6,
+		});
+	});
+
+	it("surfaces worker errors as rejections", async () => {
+		control.mode = "fail";
+		const worker = getTranslationWorker();
+		if (!worker) return;
+		await expect(worker.prepare("nl", "com")).rejects.toThrow("worker boom");
+	});
+});
+
+afterAll(() => {
+	process.env.NODE_ENV = savedNodeEnv;
+	if (savedVitest === undefined) delete process.env.VITEST;
+	else process.env.VITEST = savedVitest;
+});