chore: 移除项目内无用代码（28 文件）

- 清理任务面板/SPA 化改造遗留的未使用变量与函数（模板管理配套 6 函数、
  payloadForDisplay/showTip/hasRunning/schedulePoll/removeMatchedRowLocally 等 30+ 处）
- 清理未使用 import（getBrandTemplateXlsxUrl/uploadTempFileToJava/getProductRiskTasksBatch 等）
- useTaskProgressLoop 改为仅类型导入；progress/task-request 缓存未用参数精简
- DeleteBrandRunService 删除永不执行的 taskItems 死分支
- 全量 vue-tsc（含 --noUnusedLocals/--noUnusedParameters）0 错误；648 测试全过

frontend-vue/src/pages/image/ImageWorkbenchPage.vue

@@ -659,10 +659,6 @@ function refreshModalFooter() {
   modalShow.workspaceRegenerate = src === 'workspace'
 }
 
-function imageModalVisible(img: string) {
-  return img.startsWith('data:') || img.startsWith('http')
-}
-
 function openImageModal(images: string[], index: number, opts?: ModalSourceOpts) {
   const o = opts || {}
   imageModalImages.value = (Array.isArray(images) ? images : [images]).map(String)
@@ -765,10 +761,6 @@ function triggerBlobDownload(blob: Blob, filename: string) {
   URL.revokeObjectURL(blobUrl)
 }
 
-async function modalDownloadCurrent() {
-  const src = imageModalImages.value[imageModalIndex.value]
-  await downloadImage(src, `原图_${imageModalIndex.value + 1}.png`)
-}
 async function modalBatchDownload() {
   for (let i = 0; i < imageModalImages.value.length; i++) {
     await downloadImage(imageModalImages.value[i], `image_${i + 1}.png`)