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/actions/test-helpers.test.ts

@@ -0,0 +1,50 @@
+import { describe, expect, it, vi } from "vitest";
+import {
+	createMockAuth,
+	createMockDb,
+	createMockLogStaffActivity,
+	createMockRevalidatePath,
+	createMockRcon,
+} from "./test-helpers";
+
+describe("test-helpers", () => {
+	it("createMockDb returns vi.fn-backed query methods", () => {
+		const db = createMockDb();
+		expect(Object.keys(db).sort()).toEqual(["delete", "insert", "select", "update"]);
+		for (const method of ["insert", "update", "delete", "select"]) {
+			expect(db[method as keyof typeof db]).toBeTypeOf("function");
+			expect(vi.isMockFunction(db[method as keyof typeof db])).toBe(true);
+		}
+	});
+
+	it("createMockAuth returns next-auth-like object", () => {
+		const auth = createMockAuth();
+		expect(auth).toEqual({ auth: expect.any(Function), handlers: {}, signOut: expect.any(Function) });
+		expect(vi.isMockFunction(auth.auth)).toBe(true);
+		expect(vi.isMockFunction(auth.signOut)).toBe(true);
+	});
+
+	it("createMockRcon exposes the RCON command surface", () => {
+		const rcon = createMockRcon();
+		expect(Object.keys(rcon).sort()).toEqual([
+			"alertUser",
+			"disconnectUser",
+			"giveBadge",
+			"giveCredits",
+			"muteUser",
+			"removeBadge",
+			"unmuteUser",
+		]);
+		for (const fn of Object.values(rcon)) {
+			expect(vi.isMockFunction(fn)).toBe(true);
+		}
+	});
+
+	it("createMockLogStaffActivity and createMockRevalidatePath return fresh mocks", () => {
+		expect(vi.isMockFunction(createMockLogStaffActivity())).toBe(true);
+		expect(vi.isMockFunction(createMockRevalidatePath())).toBe(true);
+		const a = createMockRevalidatePath();
+		const b = createMockRevalidatePath();
+		expect(a).not.toBe(b);
+	});
+});