fix: resolve lint issues (XSS K601, knip unused exports, eslint errors)

- Fix XSS warnings in user.tsx by adding safe attribute to elements
- Remove unused exports: ChunkUploadRequest, getArchiveInfo,
  getFileForDirectDownload, createDirectDownloadHeaders, createConverterArchive
- Fix eslint no-unused-vars errors across multiple files
- Fix pdfmathtranslate async Promise executor issue
- Update tests to use toThrow instead of toMatch for Error objects
- Apply prettier formatting

public/script.js

@@ -1,6 +1,5 @@
 const webroot = document.querySelector("meta[name='webroot']").content;
 const fileInput = document.querySelector('input[type="file"]');
-const dropZone = document.getElementById("dropzone");
 const convertButton = document.querySelector("input[type='submit']");
 const fileNames = [];
 let fileType;