refactor(品牌工具页): 抽取 formatDateTime 与 uploadPathsToJava 公共工具

- 新增 shared/utils/datetime.ts：13 个品牌页逐字重复的 formatDateTime 收敛为一处；
  语义不同的 3 个变体（toLocaleString / 字符串切片 / 支持时间戳）保留不动
- 新增 shared/utils/upload-to-java.ts：10 个品牌页的上传循环收敛，api 依赖注入便于单测；
  保留 uploadOss（品牌Tab）与 returnEmptyWhenUnavailable（跟价）两处行为差异
- 补 datetime / upload-to-java 单测 10 例

净减约 327 行；vue-tsc 构建与 690 个前端单测全通过

frontend-vue/src/pages/brand/components/BrandPriceTrackTab.vue

@@ -257,6 +257,8 @@ import {
   type PriceTrackShopQueueItem,
   type PriceTrackTaskDetailVo,
 } from '@/shared/api/java-modules'
+import { formatDateTime } from '@/shared/utils/datetime'
+import { uploadPathsToJava } from '@/shared/utils/upload-to-java'
 
 const ziniaoVersion = useZiniaoVersion()
 
@@ -336,19 +338,6 @@ function snapTask(item: PriceTrackHistoryItem) {
   return item.taskId ? taskSnapshots.value[item.taskId]?.task : undefined
 }
 
-function formatDateTime(value?: string) {
-  if (!value) return '-'
-  const date = new Date(value)
-  if (Number.isNaN(date.getTime())) return value
-  const year = date.getFullYear()
-  const month = String(date.getMonth() + 1).padStart(2, '0')
-  const day = String(date.getDate()).padStart(2, '0')
-  const hours = String(date.getHours()).padStart(2, '0')
-  const minutes = String(date.getMinutes()).padStart(2, '0')
-  const seconds = String(date.getSeconds()).padStart(2, '0')
-  return year + '-' + month + '-' + day + ' ' + hours + ':' + minutes + ':' + seconds
-}
-
 const pollTimer = ref<number | null>(null)
 const pollingInFlight = ref(false)
 let disposed = false
@@ -511,7 +500,7 @@ async function selectAsinFile() {
   }
   try {
     asinFiles.value = paths
-    asinUploadedFiles.value = await uploadAsinPathsToJava(paths)
+    asinUploadedFiles.value = await uploadPathsToJava(getPywebviewApi(), paths, { returnEmptyWhenUnavailable: true })
     ElMessage.success(`已选择 ${paths.length} 个ASIN文件`)
   } catch (error) {
     // 上传失败时清空选择，避免本地路径残留被当作服务器路径提交给 Java
@@ -537,7 +526,7 @@ async function selectAsinFolder() {
     }
     if (!(await passGuard(checkSelectedFiles(result.items, { allowedExtensions: EXCEL_CSV_EXTENSIONS })))) return
     asinFiles.value = result.items.map((item) => item.relativePath || item.absolutePath)
-    asinUploadedFiles.value = await uploadAsinPathsToJava(result.items)
+    asinUploadedFiles.value = await uploadPathsToJava(getPywebviewApi(), result.items, { returnEmptyWhenUnavailable: true })
     ElMessage.success(`已选择文件夹内 ${result.items.length} 个ASIN文件`)
   } catch (error) {
     // 上传失败时清空选择，避免残留上一批文件让用户误以为新文件已就绪
@@ -550,24 +539,6 @@ async function selectAsinFolder() {
 
 
 // ========== 国家顺序相关 ==========
-async function uploadAsinPathsToJava(paths: Array<string | { absolutePath: string; relativePath?: string }>) {
-  const api = getPywebviewApi()
-  if (!api?.upload_file_to_java) {
-    return []
-  }
-  const uploaded: UploadedJavaFile[] = []
-  for (const item of paths) {
-    const filePath = typeof item === 'string' ? item : item.absolutePath
-    const relativePath = typeof item === 'string' ? undefined : item.relativePath
-    const result = await api.upload_file_to_java(filePath, relativePath)
-    if (!result?.success || !result.data) {
-      throw new Error(result?.error || result?.message || `上传失败：${filePath}`)
-    }
-    uploaded.push(result.data)
-  }
-  return uploaded
-}
-
 function resolveAsinRequestPaths() {
   // 提交上传返回的 fileKey（与去重/转换/采集等模块一致）：服务端按 key 反查上传临时目录，
   // 不依赖上传返回的 localPath 绝对路径形态——安全加固后服务端按拼接解析绝对路径会失败。