Make Zotero script comment dynamic and assert valid JS

The generated script's setup comment hardcoded school.second-brain.ru
even though baseUrl is already interpolated elsewhere in the template,
so the comment would lie on any other host. Also add a regression test
that the generated script parses as valid JavaScript, to catch escaping
mistakes in the template literal.

src/lib/clean-pdf/__tests__/zotero-script.test.ts

@@ -9,4 +9,9 @@ describe("buildZoteroScript", () => {
     expect(s).toContain("/api/pdf?url=");
     expect(s).not.toContain("YOUR_KEY");
   });
+
+  it("генерирует синтаксически валидный JS", () => {
+    const s = buildZoteroScript({ apiKey: "sbpdf_test123", baseUrl: "https://school.second-brain.ru" });
+    expect(() => new Function(s)).not.toThrow();
+  });
 });

src/lib/clean-pdf/zotero-script.ts

@@ -1,7 +1,7 @@
 // Адаптация скрипта Clean PDF (pdf.brainysnipe.ru/zotero-script.js) под школу.
 export function buildZoteroScript({ apiKey, baseUrl }: { apiKey: string; baseUrl: string }): string {
   return `// ── Настройки ──────────────────────────────────────────────────────────────
-const API_KEY     = '${apiKey}'; // персональный ключ из school.second-brain.ru/tools/clean-pdf
+const API_KEY     = '${apiKey}'; // персональный ключ из ${baseUrl}/tools/clean-pdf
 const SERVICE_URL = '${baseUrl}';
 const FORMAT      = 'A4';    // 'A4' или 'Letter'
 const THEME       = 'light'; // 'light' или 'dark'