fix(提示语): 失败提示优先展示后端真实原因，修正 10+ 处误导文案

上架/删除品牌/去重/转换/拆分/撤回/查ASIN/产品风险/跟价/巡店/店铺匹配/视频工作台：
- 解析失败不再只报通用文案，逐条展示后端文件级 errorMessage（上架新增「店铺未找到」专属弹窗）
- 匹配失败不再一律「请检查店铺名」，按 matchStatus 区分 CONFLICT/PENDING
- 去重/转换/拆分全失败弹窗优先列各文件真实原因，取不到才回退猜测文案
- dispatch-guard 新增 fileErrors 选项与 collectDistinctErrors 导出

frontend-vue/tests/dispatch-guard.test.ts

@@ -7,6 +7,7 @@ import {
   checkParseResult,
   checkQueuePayload,
   checkSelectedFiles,
+  collectDistinctErrors,
   extensionOf,
   findUnsafeJsonPaths,
   guardPassed,
@@ -165,6 +166,55 @@ test('test_task_101_dispatch_guard_boundary_parse_result_zero_rows_blocked', ()
   assert.match(emptyFile.message, /没有读到任何数据行/)
 })
 
+test('test_task_101_dispatch_guard_parse_result_file_errors_shown_instead_of_empty_file', () => {
+  // 2026-09-17：店铺未录入后台导致文件级失败，用户被「空文件」文案误导反复重传
+  const result = checkParseResult(parseVo({ totalRows: 0, acceptedRows: 0 }), {
+    fileErrors: ['后台店铺管理中未找到店铺：林清斌，请先添加店铺信息'],
+  })
+  assert.equal(result.ok, false)
+  assert.deepEqual(codes(result), ['parse.file-failed'])
+  assert.match(result.message, /林清斌/)
+  assert.ok(!result.message.includes('没有读到任何数据行'), '有具体原因时不展示通用空文件文案')
+})
+
+test('test_task_101_dispatch_guard_parse_result_file_errors_dedupe_blank_and_limit', () => {
+  const deduped = checkParseResult(parseVo({ totalRows: 0, acceptedRows: 0 }), {
+    fileErrors: ['店铺未匹配', '  ', '店铺未匹配', '', '第二条原因'],
+  })
+  assert.deepEqual(codes(deduped), ['parse.file-failed'])
+  assert.equal(
+    deduped.message.split('\n').filter((line) => line.startsWith('· ')).length,
+    2,
+    '空串与重复原因不应重复展示',
+  )
+
+  const many = checkParseResult(parseVo({ totalRows: 0, acceptedRows: 0 }), {
+    fileErrors: Array.from({ length: 10 }, (_, index) => `原因 ${index}`),
+  })
+  assert.match(many.message, /另有 2 条不同原因/)
+})
+
+test('test_task_101_dispatch_guard_parse_result_blank_file_errors_fallback_to_empty_file', () => {
+  const result = checkParseResult(parseVo({ totalRows: 0, acceptedRows: 0 }), {
+    fileErrors: ['  ', ''],
+  })
+  assert.deepEqual(codes(result), ['parse.empty-file'])
+})
+
+test('test_task_101_dispatch_guard_collect_distinct_errors', () => {
+  assert.deepEqual(collectDistinctErrors(['a', '  ', 'a', '', 'b']), ['a', 'b'], '去空去重且保持顺序')
+  assert.deepEqual(collectDistinctErrors(['  店铺未找到  ']), ['店铺未找到'], '首尾空白裁剪')
+  assert.deepEqual(collectDistinctErrors([]), [])
+  assert.deepEqual(collectDistinctErrors(undefined), [])
+  assert.deepEqual(collectDistinctErrors([null, 7, undefined]), [], '非字符串项忽略')
+})
+
+test('test_task_101_dispatch_guard_parse_result_file_errors_ignored_when_rows_present', () => {
+  const result = checkParseResult(parseVo(), { fileErrors: ['某文件失败'] })
+  assert.equal(result.ok, true)
+  assert.equal(result.needsConfirm, false)
+})
+
 test('test_task_101_dispatch_guard_parse_result_zero_rows_allowed_when_not_required', () => {
   const result = checkParseResult(parseVo({ totalRows: 0, acceptedRows: 0 }), { requireRows: false })
   assert.equal(result.ok, true)