Function downloadFile

src/services/exportService.ts:280–290

(content: string, filename: string, mimeType: string)

// 下载文件到本地
function downloadFile(content: string, filename: string, mimeType: string): void {
  const blob = new Blob([content], { type: mimeType })
  const url = URL.createObjectURL(blob)
  const link = document.createElement('a')
  link.href = url
  link.download = filename
  document.body.appendChild(link)
  link.click()
  document.body.removeChild(link)
  URL.revokeObjectURL(url)
}

// 获取日期字符串（格式：YYYY-MM-DD）
function getDateString(): string {