task-105(任务与重复分析中心): 实现视频任务批量选择

新增 src/pages/tasks/image-video-selection.ts：卡片选择的纯 Set 操作
(切换/批量/全选判定/半选判定)。

TDD: task-105.test.ts 8 用例先 RED 后 GREEN。

admin-frontend-vue/src/pages/tasks/image-video-selection.ts

@@ -0,0 +1,48 @@
+/** 视频卡片批量选择状态（任务 105）：不变量优先的纯 Set 操作，无框架依赖。 */
+
+/** 空选择集。 */
+export function clearVideoSelection(): Set<string> {
+  return new Set<string>()
+}
+
+function validKey(key: string): boolean {
+  return typeof key === 'string' && key.length > 0
+}
+
+/** 切换单卡选择(有则移除、无则加入)。 */
+export function videoSelectionToggle(selection: Set<string>, key: string): Set<string> {
+  const next = new Set(selection)
+  if (!validKey(key)) return next
+  if (next.has(key)) next.delete(key)
+  else next.add(key)
+  return next
+}
+
+/** 批量加入(幂等)。 */
+export function videoSelectionAdd(selection: Set<string>, keys: readonly string[]): Set<string> {
+  const next = new Set(selection)
+  for (const key of keys) if (validKey(key)) next.add(key)
+  return next
+}
+
+/** 批量移除(缺失键无操作)。 */
+export function videoSelectionRemove(selection: Set<string>, keys: readonly string[]): Set<string> {
+  const next = new Set(selection)
+  for (const key of keys) next.delete(key)
+  return next
+}
+
+export function countVideoSelection(selection: Set<string>): number {
+  return selection.size
+}
+
+/** 是否全部卡被选中(空卡列表视作未全选)。 */
+export function allCardsSelected(selection: Set<string>, keys: readonly string[]): boolean {
+  return keys.length > 0 && keys.every((key) => selection.has(key))
+}
+
+/** 是否部分卡被选中(部分但非全部)。 */
+export function partialCardsSelected(selection: Set<string>, keys: readonly string[]): boolean {
+  const selectedCount = keys.filter((key) => selection.has(key)).length
+  return selectedCount > 0 && selectedCount < keys.length
+}

admin-frontend-vue/tests/task-105.test.ts

@@ -0,0 +1,67 @@
+import test from 'node:test'
+import assert from 'node:assert/strict'
+import { readSource } from './helpers.ts'
+import {
+  allCardsSelected,
+  clearVideoSelection,
+  countVideoSelection,
+  partialCardsSelected,
+  videoSelectionAdd,
+  videoSelectionRemove,
+  videoSelectionToggle,
+} from '../src/pages/tasks/image-video-selection.ts'
+
+test('test_task_105_video_selection_normal_primary_path', () => {
+  // 正常主路径：切换单卡选择(加/减)结果正确。
+  const s1 = videoSelectionToggle(new Set(), '11:0')
+  assert.equal(countVideoSelection(s1), 1)
+  assert.ok(s1.has('11:0'))
+  const s2 = videoSelectionToggle(s1, '11:0')
+  assert.equal(countVideoSelection(s2), 0, '再次切换取消选择')
+})
+
+test('test_task_105_video_selection_normal_variant_input', () => {
+  // 正常变体：批量添加多卡。
+  const s = videoSelectionAdd(new Set(), ['11:0', '12:1', '11:0'])
+  assert.equal(countVideoSelection(s), 2, '重复键不重复计数')
+  assert.ok(s.has('12:1'))
+})
+
+test('test_task_105_video_selection_repeated_is_idempotent', () => {
+  // 正常重复：同一键重复添加幂等；操作不污染入参。
+  const input = new Set(['a'])
+  assert.deepEqual(videoSelectionAdd(input, ['a']), new Set(['a']))
+  assert.deepEqual([...input], ['a'])
+})
+
+test('test_task_105_video_selection_boundary_empty_input', () => {
+  // 边界空值：空选择计数为 0，全不选。
+  assert.equal(countVideoSelection(new Set()), 0)
+  assert.equal(allCardsSelected(new Set(), ['a', 'b']), false)
+})
+
+test('test_task_105_video_selection_boundary_single_item', () => {
+  // 边界单元素：仅一卡时选中=全选。
+  assert.equal(allCardsSelected(new Set(['a']), ['a']), true)
+  assert.equal(partialCardsSelected(new Set(['a']), ['a']), false)
+})
+
+test('test_task_105_video_selection_boundary_limit_or_missing_field', () => {
+  // 边界上限/缺字段：移除未选键为无操作。
+  const s = videoSelectionRemove(new Set(['a']), ['x'])
+  assert.deepEqual([...s], ['a'])
+})
+
+test('test_task_105_video_selection_invalid_input_rejected', () => {
+  // 异常输入：空字符串键被忽略。
+  const s = videoSelectionToggle(new Set(), '')
+  assert.equal(countVideoSelection(s), 0)
+  assert.deepEqual([...clearVideoSelection()], [])
+})
+
+test('test_task_105_video_selection_dependency_failure_returns_actionable_message', () => {
+  // 依赖失败/可操作：选择状态纯逻辑、无框架/http。
+  const mod = readSource('src/pages/tasks/image-video-selection.ts')
+  assert.equal(/axios|http\.|vue/.test(mod), false, '选择模块保持纯逻辑')
+  assert.match(mod, /partialCardsSelected/)
+})