task-116(任务与重复分析中心): 实现重复检查分布视图

新增 duplicate-distribution.ts：按国家/站点聚合撞款分布与撞款 ASIN top 店铺。

TDD: task-116.test.ts 8 用例先 RED 后 GREEN。

admin-frontend-vue/src/pages/tasks/duplicate-distribution.ts

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+/** 重复检查分布视图（任务 116）：按国家/站点聚合撞款与 top 店铺分布；纯逻辑。 */
+import type { DuplicateShop } from './duplicate-model.ts'
+
+export interface CountryDistributionRow {
+  country: string
+  asinCount: number
+  shopCount: number
+}
+
+/** 按国家聚合分布(每店铺 country_codes 全量计入)。 */
+export function countryDistribution(shops: readonly DuplicateShop[]): CountryDistributionRow[] {
+  const byCountry = new Map<string, { asinCount: number; shopCount: number }>()
+  for (const item of shops) {
+    for (const code of item.countryCodes) {
+      const country = code.trim().toUpperCase()
+      if (!country) continue
+      const entry = byCountry.get(country) ?? { asinCount: 0, shopCount: 0 }
+      entry.asinCount += item.asinCount
+      entry.shopCount += 1
+      byCountry.set(country, entry)
+    }
+  }
+  return [...byCountry.entries()]
+    .map(([country, entry]) => ({ country, asinCount: entry.asinCount, shopCount: entry.shopCount }))
+    .sort((a, b) => b.asinCount - a.asinCount || a.country.localeCompare(b.country))
+}
+
+export interface SiteDistributionRow {
+  site: string
+  asinCount: number
+  shopCount: number
+}
+
+/** 按站点(site)聚合：以单国家维度汇总撞款，站点取国家码。 */
+export function duplicateSiteDistribution(shops: readonly DuplicateShop[]): SiteDistributionRow[] {
+  const rows = countryDistribution(shops)
+  return rows.map((row) => ({ site: row.country, asinCount: row.asinCount, shopCount: row.shopCount }))
+}
+
+/** 按撞款 ASIN 数取 top 店铺(降序)，limit<=0 返回空。 */
+export function topShopsByAsin(shops: readonly DuplicateShop[], limit: number): DuplicateShop[] {
+  if (!(limit > 0)) return []
+  return [...shops]
+    .sort((a, b) => b.asinCount - a.asinCount || a.shopName.localeCompare(b.shopName))
+    .slice(0, Math.floor(limit))
+}

admin-frontend-vue/tests/task-116.test.ts

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+import test from 'node:test'
+import assert from 'node:assert/strict'
+import { readSource } from './helpers.ts'
+import {
+  countryDistribution,
+  duplicateSiteDistribution,
+  topShopsByAsin,
+} from '../src/pages/tasks/duplicate-distribution.ts'
+import type { DuplicateShop } from '../src/pages/tasks/duplicate-model.ts'
+
+function shop(shopName: string, countryCodes: string[], asinCount: number): DuplicateShop {
+  return { shopName, groupName: '', countryCodes, asinCount, recordCount: 0 }
+}
+
+test('test_task_116_duplicate_distribution_normal_primary_path', () => {
+  // 正常主路径：按国家/站点聚合撞款分布(合计 asin 与店铺数)。
+  const shops = [shop('A', ['DE', 'UK'], 10), shop('B', ['DE'], 5), shop('C', ['FR'], 3)]
+  const dist = countryDistribution(shops)
+  const de = dist.find((d) => d.country === 'DE')
+  assert.equal(de!.asinCount, 15)
+  assert.equal(de!.shopCount, 2)
+  assert.equal(dist.length, 3)
+})
+
+test('test_task_116_duplicate_distribution_normal_variant_input', () => {
+  // 正常变体：site 取单国家码首字段。
+  const dist = duplicateSiteDistribution([shop('A', ['DE'], 4)])
+  assert.equal(dist.length, 1)
+  assert.equal(dist[0].site, 'DE')
+  assert.equal(dist[0].asinCount, 4)
+})
+
+test('test_task_116_duplicate_distribution_repeated_is_idempotent', () => {
+  // 正常重复：聚合稳定、不改输入。
+  const shops = [shop('A', ['DE'], 3)]
+  assert.deepEqual(countryDistribution(shops), countryDistribution(shops))
+  assert.equal(shops[0].asinCount, 3)
+})
+
+test('test_task_116_duplicate_distribution_boundary_empty_input', () => {
+  // 边界空值：空店铺列表无分布。
+  assert.deepEqual(countryDistribution([]), [])
+  assert.deepEqual(topShopsByAsin([], 5), [])
+})
+
+test('test_task_116_duplicate_distribution_boundary_single_item', () => {
+  // 边界单元素：单店单国家。
+  const dist = countryDistribution([shop('A', ['UK'], 2)])
+  assert.equal(dist.length, 1)
+  assert.equal(dist[0].shopCount, 1)
+})
+
+test('test_task_116_duplicate_distribution_boundary_limit_or_missing_field', () => {
+  // 边界上限/缺字段：无国家的店铺不计入国家分布。
+  const dist = countryDistribution([shop('A', [], 7)])
+  assert.deepEqual(dist, [])
+})
+
+test('test_task_116_duplicate_distribution_invalid_input_rejected', () => {
+  // 异常输入：top 负数回空或 0 条。
+  assert.deepEqual(topShopsByAsin([shop('A', ['DE'], 9)], 0), [])
+})
+
+test('test_task_116_duplicate_distribution_dependency_failure_returns_actionable_message', () => {
+  // 依赖失败/可操作：分布计算纯逻辑、无框架/http。
+  const mod = readSource('src/pages/tasks/duplicate-distribution.ts')
+  assert.equal(/axios|http\.|vue/.test(mod), false, '分布计算保持纯逻辑')
+  assert.match(mod, /topShopsByAsin/)
+})