export function downloadCsv(filename: string, rows: string[][]) {
  const escape = (cell: string) => {
    const s = String(cell ?? "");
    if (/[",\n\r]/.test(s)) return `"${s.replace(/"/g, '""')}"`;
    return s;
  };

  const content = rows.map((row) => row.map(escape).join(",")).join("\r\n");
  const blob = new Blob(["\uFEFF" + content], { type: "text/csv;charset=utf-8;" });
  const url = URL.createObjectURL(blob);
  const link = document.createElement("a");
  link.href = url;
  link.download = filename;
  link.click();
  URL.revokeObjectURL(url);
}