diff --git a/frontend-vue/src/shared/composables/useTaskProgressLoop.ts b/frontend-vue/src/shared/composables/useTaskProgressLoop.ts
index bb430f38..3ee14dc0 100644
--- a/frontend-vue/src/shared/composables/useTaskProgressLoop.ts
+++ b/frontend-vue/src/shared/composables/useTaskProgressLoop.ts
@@ -5,6 +5,10 @@ import {
   createTaskPollingBaseline,
   type TaskPollingBaseline,
 } from '@/shared/task-polling-baseline'
+import {
+  createProgressResponseCache,
+  type ProgressResponseCache,
+} from '@/shared/progress-response-cache'
 
 /**
  * 通用任务进度轮询组合式函数。
@@ -56,6 +60,12 @@ export interface TaskProgressLoopOptions<TDetail> {
    * 响应体大小与缓存内存占用。
    */
   onBaseline?: (baseline: TaskPollingBaseline) => void
+  /**
+   * 可选进度响应缓存（Task 82）：传入后每轮响应快照按 taskId 写入
+   * TTL+最大条目数的有界缓存（读取时惰性清理过期条目），供页面在
+   * 轮询间隙复用最近一次进度快照。
+   */
+  progressCache?: ProgressResponseCache<TDetail>
 }
 
 export interface TaskProgressLoopHandle<TDetail> {
@@ -167,6 +177,7 @@ export function useTaskProgressLoop<TDetail>(
         } catch {
           /* onUpdate 抛错不应中断本轮 */
         }
+        options.progressCache?.set(id, detail)
         if (status) {
           nextStatuses[id] = status
           if (isTerminal(status)) {
diff --git a/frontend-vue/src/shared/progress-response-cache.ts b/frontend-vue/src/shared/progress-response-cache.ts
new file mode 100644
index 00000000..b7a53cbc
--- /dev/null
+++ b/frontend-vue/src/shared/progress-response-cache.ts
@@ -0,0 +1,141 @@
+/**
+ * 进度响应 Map（Task 82）。
+ *
+ * 为前端任务轮询的进度响应快照提供带 TTL 与最大条目数的内存缓存：
+ * - 条目在写入后 ttlMs 毫秒过期，读取/枚举/清理时惰性移除；
+ * - 条目数超过 maxEntries 时驱逐最旧条目（首次写入顺序），缓存始终有界；
+ * - 时钟可注入（now），测试可用虚拟时钟验证 TTL 边界，不依赖真实时间。
+ *
+ * 纯 TS 无副作用模块；set 对非法 key 抛出「key 必须是正整数」错误（fail-fast），
+ * 时钟抛错时 set 不留下任何部分写入；读取路径（get/has/delete）对非法 key 宽容。
+ * 供 useTaskProgressLoop 的可选缓存选项复用。
+ */
+export interface ProgressResponseCacheOptions {
+  /** 条目过期时间（毫秒），必须为正数 */
+  ttlMs: number
+  /** 缓存最大条目数，必须为正数 */
+  maxEntries: number
+  /** 时钟来源；默认 Date.now()，测试可注入虚拟时钟 */
+  now?: () => number
+}
+
+interface Entry<V> {
+  value: V
+  createdAt: number
+}
+
+export function createProgressResponseCache<V>(options: ProgressResponseCacheOptions) {
+  const ttlMs = options.ttlMs
+  const maxEntries = options.maxEntries
+  const now = options.now ?? Date.now
+  if (!(ttlMs > 0)) {
+    throw new Error('ttlMs 必须为正数: ' + ttlMs)
+  }
+  if (!(maxEntries > 0)) {
+    throw new Error('maxEntries 必须为正数: ' + maxEntries)
+  }
+
+  const map = new Map<number, Entry<V>>()
+
+  function validateKey(key: number): boolean {
+    return Number.isFinite(key) && key > 0 && Number.isInteger(key)
+  }
+
+  function isExpired(entry: Entry<V>, at: number): boolean {
+    return at - entry.createdAt >= ttlMs
+  }
+
+  function purgeExpired(): number {
+    const at = now()
+    let removed = 0
+    for (const [key, entry] of map) {
+      if (isExpired(entry, at)) {
+        map.delete(key)
+        removed += 1
+      }
+    }
+    return removed
+  }
+
+  function evictIfNeeded(at: number) {
+    while (map.size > maxEntries) {
+      const oldest = map.keys().next().value as number | undefined
+      if (oldest == null) break
+      map.delete(oldest)
+    }
+  }
+
+  function set(key: number, value: V) {
+    if (!validateKey(key)) {
+      throw new Error('key 必须是正整数: ' + key)
+    }
+    const createdAt = now()
+    if (map.has(key)) {
+      map.set(key, { value, createdAt })
+    } else {
+      map.set(key, { value, createdAt })
+      evictIfNeeded(createdAt)
+    }
+  }
+
+  function get(key: number): V | undefined {
+    if (!validateKey(key)) return undefined
+    const at = now()
+    const entry = map.get(key)
+    if (!entry) return undefined
+    if (isExpired(entry, at)) {
+      map.delete(key)
+      return undefined
+    }
+    return entry.value
+  }
+
+  function has(key: number): boolean {
+    if (!validateKey(key)) return false
+    const at = now()
+    const entry = map.get(key)
+    if (!entry) return false
+    if (isExpired(entry, at)) {
+      map.delete(key)
+      return false
+    }
+    return true
+  }
+
+  function deleteEntry(key: number): boolean {
+    if (!validateKey(key)) return false
+    return map.delete(key)
+  }
+
+  function clear() {
+    map.clear()
+  }
+
+  function entries(): Array<[number, V]> {
+    const at = now()
+    const result: Array<[number, V]> = []
+    for (const [key, entry] of map) {
+      if (isExpired(entry, at)) {
+        map.delete(key)
+        continue
+      }
+      result.push([key, entry.value])
+    }
+    return result
+  }
+
+  return {
+    get size() {
+      return map.size
+    },
+    set,
+    get,
+    has,
+    delete: deleteEntry,
+    clear,
+    entries,
+    purgeExpired,
+  }
+}
+
+export type ProgressResponseCache<V> = ReturnType<typeof createProgressResponseCache<V>>
diff --git a/frontend-vue/tests/progress-response-cache.test.ts b/frontend-vue/tests/progress-response-cache.test.ts
new file mode 100644
index 00000000..2e1b8915
--- /dev/null
+++ b/frontend-vue/tests/progress-response-cache.test.ts
@@ -0,0 +1,209 @@
+import { test } from 'node:test'
+import assert from 'node:assert/strict'
+import { createProgressResponseCache } from '../src/shared/progress-response-cache.ts'
+
+interface FakeDetail {
+  id: number
+  name: string
+  status: string
+}
+
+function detail(id: number): FakeDetail {
+  return { id, name: `task-${id}`, status: id % 2 === 0 ? 'SUCCESS' : 'RUNNING' }
+}
+
+function clock(start = 1000) {
+  let now = start
+  return {
+    now: () => now,
+    tick: (ms: number) => {
+      now += ms
+    },
+  }
+}
+
+test('test_task_082_progress_cleanup_normal_default_path', () => {
+  const c = clock()
+  const cache = createProgressResponseCache<FakeDetail>({
+    ttlMs: 30_000,
+    maxEntries: 500,
+    now: c.now,
+  })
+  cache.set(1, detail(1))
+  assert.deepEqual(cache.get(1), detail(1))
+  assert.equal(cache.has(1), true)
+  assert.equal(cache.size, 1)
+  assert.deepEqual(cache.entries(), [[1, detail(1)]])
+})
+
+test('test_task_082_progress_cleanup_normal_multiple_items', () => {
+  const c = clock()
+  const cache = createProgressResponseCache<FakeDetail>({
+    ttlMs: 60_000,
+    maxEntries: 10,
+    now: c.now,
+  })
+  for (let i = 1; i <= 10; i++) cache.set(i, detail(i))
+  assert.equal(cache.size, 10)
+  assert.deepEqual(
+    cache.entries().map(([k]) => k),
+    [1, 2, 3, 4, 5, 6, 7, 8, 9, 10],
+  )
+  assert.deepEqual(
+    cache.entries().map(([, v]) => v.id),
+    [1, 2, 3, 4, 5, 6, 7, 8, 9, 10],
+  )
+})
+
+test('test_task_082_progress_cleanup_normal_repeated_operation_is_idempotent', () => {
+  const c = clock()
+  const cache = createProgressResponseCache<FakeDetail>({
+    ttlMs: 60_000,
+    maxEntries: 10,
+    now: c.now,
+  })
+  cache.set(1, detail(1))
+  cache.set(1, { ...detail(1), status: 'SUCCESS' })
+  assert.equal(cache.size, 1)
+  assert.equal(cache.get(1)?.status, 'SUCCESS')
+  cache.set(1, { ...detail(1), status: 'SUCCESS' })
+  assert.equal(cache.size, 1)
+  assert.deepEqual(
+    cache.entries().map(([k]) => k),
+    [1],
+  )
+  // 更新已存在条目不改变插入顺序
+  cache.set(2, detail(2))
+  cache.set(1, detail(1))
+  assert.deepEqual(
+    cache.entries().map(([k]) => k),
+    [1, 2],
+  )
+})
+
+test('test_task_082_progress_cleanup_boundary_empty_input', () => {
+  const c = clock()
+  const cache = createProgressResponseCache<FakeDetail>({
+    ttlMs: 1000,
+    maxEntries: 5,
+    now: c.now,
+  })
+  assert.equal(cache.size, 0)
+  assert.equal(cache.get(1), undefined)
+  assert.equal(cache.has(1), false)
+  assert.deepEqual(cache.entries(), [])
+  assert.equal(cache.purgeExpired(), 0)
+  cache.clear()
+  assert.equal(cache.size, 0)
+  assert.equal(cache.purgeExpired(), 0)
+})
+
+test('test_task_082_progress_cleanup_boundary_single_item', () => {
+  const c = clock()
+  const cache = createProgressResponseCache<FakeDetail>({
+    ttlMs: 1000,
+    maxEntries: 5,
+    now: c.now,
+  })
+  cache.set(7, detail(7))
+  assert.deepEqual(cache.get(7), detail(7))
+  assert.equal(cache.size, 1)
+  assert.equal(cache.has(7), true)
+  c.tick(1001)
+  assert.equal(cache.get(7), undefined)
+  assert.equal(cache.has(7), false)
+  assert.equal(cache.size, 0)
+  assert.equal(cache.purgeExpired(), 0)
+})
+
+test('test_task_082_progress_cleanup_boundary_limit_and_overflow', () => {
+  // 条目数超限：驱逐最旧，缓存有界
+  const c1 = clock()
+  const byEntries = createProgressResponseCache<FakeDetail>({
+    ttlMs: 60_000,
+    maxEntries: 3,
+    now: c1.now,
+  })
+  for (let i = 1; i <= 5; i++) byEntries.set(i, detail(i))
+  assert.equal(byEntries.size, 3)
+  assert.deepEqual(
+    byEntries.entries().map(([k]) => k),
+    [3, 4, 5],
+  )
+  assert.equal(byEntries.get(1), undefined)
+  assert.equal(byEntries.get(2), undefined)
+
+  // TTL 清理：到期条目被 purgeExpired 清除
+  const c2 = clock()
+  const byTtl = createProgressResponseCache<FakeDetail>({
+    ttlMs: 10_000,
+    maxEntries: 100,
+    now: c2.now,
+  })
+  byTtl.set(1, detail(1))
+  byTtl.set(2, detail(2))
+  c2.tick(5_000)
+  byTtl.set(3, detail(3))
+  assert.equal(byTtl.purgeExpired(), 0)
+  c2.tick(5_001)
+  assert.equal(byTtl.purgeExpired(), 2)
+  assert.deepEqual(
+    byTtl.entries().map(([k]) => k),
+    [3],
+  )
+  assert.equal(byTtl.size, 1)
+  // 读取路径惰性清理
+  c2.tick(5_000)
+  assert.equal(byTtl.get(3), undefined)
+  assert.equal(byTtl.size, 0)
+  assert.equal(byTtl.purgeExpired(), 0)
+})
+
+test('test_task_082_progress_cleanup_invalid_input_rejected', () => {
+  const c = clock()
+  assert.throws(() => createProgressResponseCache({ ttlMs: 0, maxEntries: 5 }), /ttlMs 必须为正数/)
+  assert.throws(() => createProgressResponseCache({ ttlMs: -1, maxEntries: 5 }), /ttlMs 必须为正数/)
+  assert.throws(() => createProgressResponseCache({ ttlMs: 1000, maxEntries: 0 }), /maxEntries 必须为正数/)
+  assert.throws(() => createProgressResponseCache({ ttlMs: 1000, maxEntries: -5 }), /maxEntries 必须为正数/)
+  const cache = createProgressResponseCache<FakeDetail>({ ttlMs: 1000, maxEntries: 5, now: c.now })
+  assert.throws(() => cache.set(0, detail(0)), /key 必须是正整数/)
+  assert.throws(() => cache.set(-1, detail(-1)), /key 必须是正整数/)
+  assert.throws(() => cache.set(NaN, detail(NaN)), /key 必须是正整数/)
+  assert.throws(() => cache.set(1.5, detail(1.5)), /key 必须是正整数/)
+  // 读取路径宽容：非法 key 不抛错
+  assert.equal(cache.get(-1), undefined)
+  assert.equal(cache.has(0), false)
+  assert.equal(cache.delete(0), false)
+})
+
+test('test_task_082_progress_cleanup_dependency_failure_releases_resources', () => {
+  const c = clock()
+  let broken = true
+  const faultyNow = () => {
+    if (broken) throw new Error('clock down')
+    return c.now()
+  }
+  const cache = createProgressResponseCache<FakeDetail>({
+    ttlMs: 1000,
+    maxEntries: 5,
+    now: faultyNow,
+  })
+  // 时钟故障时 set 失败，缓存零状态变更
+  assert.throws(() => cache.set(1, detail(1)), /clock down/)
+  assert.equal(cache.size, 0)
+  // 故障恢复后同一实例继续工作
+  broken = false
+  cache.set(1, detail(1))
+  assert.equal(cache.get(1)?.id, 1)
+  // 时钟故障时读取/清理抛错但不破坏条目
+  broken = true
+  assert.throws(() => cache.get(1), /clock down/)
+  assert.throws(() => cache.purgeExpired(), /clock down/)
+  assert.throws(() => cache.entries(), /clock down/)
+  broken = false
+  assert.equal(cache.get(1)?.id, 1)
+  assert.equal(cache.size, 1)
+  // clear 释放全部资源
+  cache.clear()
+  assert.equal(cache.size, 0)
+})