task-113(任务与重复分析中心): 实现店铺数据任务批量下载

新增 shop-data-download.ts(打包请求体 result_ids + 下载 job 状态)，
shop-data-api.ts 增加 requestShopDataZipDownload(POST /download-zip, blob)。

TDD: task-113.test.ts 8 用例先 RED 后 GREEN。

admin-frontend-vue/src/pages/tasks/shop-data-download.ts

@@ -0,0 +1,48 @@
+/** 店铺数据结果批量下载任务（任务 113）：打包请求体与下载 job 状态；纯逻辑。 */
+
+export type ShopDataDownloadStatus = 'idle' | 'running' | 'done' | 'failed'
+
+export interface ShopDataDownloadJob {
+  status: ShopDataDownloadStatus
+  message?: string
+  fileCount?: number
+  errorCount?: number
+}
+
+function finitePositive(value: unknown): number | null {
+  const number = typeof value === 'number' && Number.isFinite(value)
+    ? value
+    : typeof value === 'string' && /^\d+$/.test(value.trim())
+      ? Number(value.trim())
+      : null
+  return number === null || number < 1 ? null : Math.floor(number)
+}
+
+/** result_id → POST /download-zip 请求体(过滤非法 id，按序去重)。 */
+export function toShopDataZipRequest(resultIds: readonly (number | string)[]): { result_ids: number[] } {
+  const ids: number[] = []
+  const seen = new Set<number>()
+  for (const id of resultIds) {
+    const parsed = finitePositive(id)
+    if (parsed === null || seen.has(parsed)) continue
+    seen.add(parsed)
+    ids.push(parsed)
+  }
+  return { result_ids: ids }
+}
+
+export function createShopDataDownloadJob(): ShopDataDownloadJob {
+  return { status: 'idle' }
+}
+
+export function startShopDataDownload(): ShopDataDownloadJob {
+  return { status: 'running' }
+}
+
+export function succeedShopDataDownload(_job: ShopDataDownloadJob, fileCount: number, errorCount: number): ShopDataDownloadJob {
+  return { status: 'done', fileCount, errorCount }
+}
+
+export function failShopDataDownload(_job: ShopDataDownloadJob, message: string): ShopDataDownloadJob {
+  return { status: 'failed', message }
+}