feat: add semantic CSS stylesheets (#3274)

Co-authored-by: Cursor Agent <cursoragent@cursor.com>

apps/server/src/workers/stylesheet-preflight.test.ts

@@ -0,0 +1,58 @@
+import { describe, expect, it, vi } from "vitest";
+import { inspectPreflightPdf } from "./stylesheet-preflight-inspection";
+
+const warning = {
+	code: "EXTREME_VALUE",
+	severity: "warning",
+	message: "The authored value is unusually large.",
+	range: {
+		start: { line: 1, column: 1, offset: 0 },
+		end: { line: 1, column: 10, offset: 9 },
+	},
+} as const;
+
+const rendered = {
+	ok: true as const,
+	bytes: new TextEncoder().encode("%PDF-1.7"),
+	diagnostics: [warning],
+};
+
+const limits = {
+	maxPages: 20,
+	maxBytes: 10_000_000,
+	maxPageWidthPt: 2_000,
+	maxPageHeightPt: 20_000,
+	maxPageAreaPt2: 20_000_000,
+};
+
+describe("stylesheet preflight PDF inspection", () => {
+	it("preserves compiler warnings and hides parser exceptions", async () => {
+		const destroy = vi.fn(async () => undefined);
+
+		const result = await inspectPreflightPdf(rendered, limits, () => ({
+			promise: Promise.reject(new Error("sensitive parser details")),
+			destroy,
+		}));
+
+		expect(result).toEqual({
+			ok: false,
+			code: "STYLESHEET_PREFLIGHT_PARSE_FAILED",
+			message: "PDF inspection failed.",
+			diagnostics: [warning],
+		});
+		expect(destroy).toHaveBeenCalledOnce();
+	});
+
+	it("preserves compiler warnings when PDF.js fails before returning a loading task", async () => {
+		const result = await inspectPreflightPdf(rendered, limits, () => {
+			throw new Error("sensitive parser setup details");
+		});
+
+		expect(result).toEqual({
+			ok: false,
+			code: "STYLESHEET_PREFLIGHT_PARSE_FAILED",
+			message: "PDF inspection failed.",
+			diagnostics: [warning],
+		});
+	});
+});