test: add unit tests for pure logic modules

Add 22 test files covering imager, soundtracks, browser-headers, source-keys (figure/pet/effect), effect-source, plus catalog-translations, catalog-layouts, client-translation-files, translations-utils, and various admin/services/helpers modules. Total test count increases by 120+.

src/lib/foundation/errors.test.ts

@@ -0,0 +1,77 @@
+import { describe, expect, it } from "vitest";
+import {
+	DatabaseError,
+	DomainError,
+	ForbiddenError,
+	NotFoundError,
+	RateLimitError,
+	UnauthorizedError,
+	ValidationError,
+} from "./errors";
+
+describe("DomainError", () => {
+	it("carries a message and status", () => {
+		const err = new DomainError("bad", 418);
+		expect(err.message).toBe("bad");
+		expect(err.status).toBe(418);
+		expect(err.name).toBe("DomainError");
+	});
+	it("defaults to HTTP 500", () => {
+		expect(new DomainError("x").status).toBe(500);
+	});
+});
+
+describe("NotFoundError", () => {
+	it("formats message with and without an id", () => {
+		expect(new NotFoundError("sofa").message).toBe("sofa not found");
+		expect(new NotFoundError("sofa", 3).message).toBe("sofa #3 not found");
+	});
+	it("uses status 404", () => {
+		expect(new NotFoundError("x").status).toBe(404);
+	});
+});
+
+describe("UnauthorizedError", () => {
+	it("defaults message and status", () => {
+		const err = new UnauthorizedError();
+		expect(err.message).toBe("Unauthorized");
+		expect(err.status).toBe(401);
+	});
+	it("accepts a custom message", () => {
+		expect(new UnauthorizedError("no token").message).toBe("no token");
+	});
+});
+
+describe("ForbiddenError", () => {
+	it("uses status 403", () => {
+		const err = new ForbiddenError();
+		expect(err.status).toBe(403);
+		expect(err.message).toBe("Forbidden");
+	});
+});
+
+describe("ValidationError", () => {
+	it("carries field errors and status 422", () => {
+		const err = new ValidationError({ name: ["too short"] });
+		expect(err.status).toBe(422);
+		expect(err.fieldErrors.name).toEqual(["too short"]);
+	});
+});
+
+describe("RateLimitError", () => {
+	it("exposes retryAfter and status 429", () => {
+		const err = new RateLimitError(12);
+		expect(err.status).toBe(429);
+		expect(err.retryAfter).toBe(12);
+		expect(err.message).toContain("12");
+	});
+});
+
+describe("DatabaseError", () => {
+	it("carries a cause and status 500", () => {
+		const cause = new Error("conn refused");
+		const err = new DatabaseError("query failed", cause);
+		expect(err.status).toBe(500);
+		expect(err.cause).toBe(cause);
+	});
+});