fix(frontend): 优化 task log 前端交互体验

- 简化虚拟滚动实现，移除 @tanstack/vue-virtual 依赖
- 添加分页组件，支持翻页查看历史任务
- 添加 SSE 指数退避重试机制（最多 3 次）
- 更新 API 接口支持分页参数
- 添加重试状态指示器

背景：前端存在虚拟滚动与 SSE 不兼容、缺少分页、连接断开无重试等问题

关联 commit：fix/logs 分支

frontend/src/api/taskLog.ts

@@ -24,10 +24,20 @@ export interface TaskLogLine {
 export interface TaskLogListParams {
   source?: string
   businessLineId?: number
+  page?: number
+  pageSize?: number
+}
+
+export interface TaskLogListResult {
+  items: TaskLogSummary[]
+  total: number
+  page: number
+  page_size: number
+  total_pages: number
 }
 
 export const taskLogApi = {
-  async list(params: TaskLogListParams = {}): Promise<TaskLogSummary[]> {
+  async list(params: TaskLogListParams = {}): Promise<TaskLogListResult> {
     const query = new URLSearchParams()
     if (params.source && params.source !== 'all') {
       query.set('source', params.source)
@@ -35,9 +45,21 @@ export const taskLogApi = {
     if (params.businessLineId) {
       query.set('business_line_id', String(params.businessLineId))
     }
+    if (params.page) {
+      query.set('page', String(params.page))
+    }
+    if (params.pageSize) {
+      query.set('page_size', String(params.pageSize))
+    }
     const suffix = query.toString() ? `?${query.toString()}` : ''
     const data = await authRequest(`/auth/api/v1/task-logs${suffix}`)
-    return Array.isArray(data.items) ? data.items : []
+    return {
+      items: Array.isArray(data.items) ? data.items : [],
+      total: data.total || 0,
+      page: data.page || 1,
+      page_size: data.page_size || 20,
+      total_pages: data.total_pages || 0,
+    }
   },
 
   async get(id: string): Promise<{ task: TaskLogSummary; lines: TaskLogLine[] }> {
@@ -89,6 +111,8 @@ export interface TaskLogStreamCallbacks {
 
 export function createTaskLogStream(taskId: string, callbacks: TaskLogStreamCallbacks): EventSource {
   const token = getToken()
+  // 注意：EventSource 不支持自定义请求头，只能通过 query parameter 传递 token
+  // TODO: 在生产环境中，应考虑使用 WebSocket 或 HttpOnly Cookie 方式以提高安全性
   const url = `/auth/api/v1/task-logs/stream?task_id=${encodeURIComponent(taskId)}&access_token=${encodeURIComponent(token || '')}`
 
   const es = new EventSource(url)

frontend/src/views/task/TaskCenter.vue

@@ -42,7 +42,11 @@
             暂无任务记录
           </div>
           <div class="pagination">
-            <span>共 {{ tasks.length }} 条 · 当前业务线：{{ currentName }}</span>
+            <span>共 {{ totalTasks }} 条 · 第 {{ currentPage }}/{{ totalPages }} 页 · 当前业务线：{{ currentName }}</span>
+            <div class="pagination-actions">
+              <el-button size="small" :disabled="currentPage <= 1" @click="prevPage">上一页</el-button>
+              <el-button size="small" :disabled="currentPage >= totalPages" @click="nextPage">下一页</el-button>
+            </div>
           </div>
         </div>
       </div>
@@ -53,6 +57,7 @@
             <span>任务日志</span>
             <span class="selected-name">{{ selectedTaskName }}</span>
             <span v-if="isStreaming" class="streaming-indicator">● 实时更新中</span>
+            <span v-if="streamRetryCount > 0" class="retry-indicator">重试中 ({{ streamRetryCount }}/3)</span>
           </h3>
           <div class="panel-actions">
             <el-switch
@@ -68,24 +73,13 @@
           class="panel-body log-stream"
           @scroll="handleScroll"
         >
-          <!-- 虚拟滚动容器 -->
+          <!-- 简单滚动容器 -->
           <div
-            :style="{ height: `${virtualizer.getTotalSize()}px`, position: 'relative' }"
+            v-for="(log, index) in logs"
+            :key="index"
+            :class="['task-log-line', log.class]"
           >
-            <div
-              v-for="virtualRow in virtualizer.getVirtualItems()"
-              :key="String(virtualRow.key)"
-              :class="['task-log-line', logs[virtualRow.index].class]"
-              :style="{
-                position: 'absolute',
-                top: 0,
-                left: 0,
-                width: '100%',
-                transform: `translateY(${virtualRow.start}px)`,
-              }"
-            >
-              <span class="t">{{ logs[virtualRow.index].time }}</span>{{ logs[virtualRow.index].message }}
-            </div>
+            <span class="t">{{ log.time }}</span>{{ log.message }}
           </div>
           <div v-if="loadingLogs" class="task-log-line">
             <span class="t">...</span>加载中
@@ -104,7 +98,6 @@ import { computed, nextTick, onMounted, onUnmounted, ref, watch } from 'vue'
 import { taskLogApi, createTaskLogStream, type TaskLogLine, type TaskLogSummary } from '@/api/taskLog'
 import { useBusinessLineStore } from '@/stores/businessLine'
 import { useBusinessLineMockProfile } from '@/utils/businessLineMock'
-import { useVirtualizer } from '@tanstack/vue-virtual'
 
 const { currentName } = useBusinessLineMockProfile()
 const businessLineStore = useBusinessLineStore()
@@ -121,13 +114,16 @@ let eventSource: EventSource | null = null
 const autoScroll = ref(true)
 const logContainerRef = ref<HTMLDivElement | null>(null)
 
-// 虚拟滚动配置
-const virtualizer = useVirtualizer({
-  count: logs.value.length,
-  getScrollElement: () => logContainerRef.value,
-  estimateSize: () => 20,
-  overscan: 5,
-})
+// 分页相关
+const currentPage = ref(1)
+const pageSize = ref(20)
+const totalTasks = ref(0)
+const totalPages = computed(() => Math.ceil(totalTasks.value / pageSize.value))
+
+// SSE 重试相关
+const streamRetryCount = ref(0)
+const maxRetryCount = 3
+let retryTimeout: ReturnType<typeof setTimeout> | null = null
 
 const selectedTask = computed(() => tasks.value.find((task) => task.id === selectedTaskId.value))
 const selectedTaskName = computed(() => selectedTask.value?.name || '未选择')
@@ -137,10 +133,14 @@ const lastLoadedText = computed(() => lastLoadedAt.value ? `更新于 ${formatTi
 async function loadTasks() {
   loadingTasks.value = true
   try {
-    tasks.value = await taskLogApi.list({
+    const result = await taskLogApi.list({
       source: sourceFilter.value,
       businessLineId: businessLineStore.current?.id,
+      page: currentPage.value,
+      pageSize: pageSize.value,
     })
+    tasks.value = result.items
+    totalTasks.value = result.total
     lastLoadedAt.value = new Date()
     if (!tasks.value.some((task) => task.id === selectedTaskId.value)) {
       selectedTaskId.value = tasks.value[0]?.id || ''
@@ -163,6 +163,7 @@ async function loadLogs(taskId: string) {
     const data = await taskLogApi.get(taskId)
     logs.value = data.lines
     lastLoadedAt.value = new Date()
+    scrollToBottom()
     // 启动 SSE 流式更新
     startStream(taskId)
   } catch (error) {
@@ -174,6 +175,7 @@ async function loadLogs(taskId: string) {
 
 function startStream(taskId: string) {
   stopStream() // 关闭之前的连接
+  streamRetryCount.value = 0
 
   eventSource = createTaskLogStream(taskId, {
     onInit: (lines) => {
@@ -182,23 +184,45 @@ function startStream(taskId: string) {
       scrollToBottom()
     },
     onUpdate: (newLines) => {
-      logs.value = [...logs.value, ...newLines]
+      logs.value = newLines
       lastLoadedAt.value = new Date()
       scrollToBottom()
     },
     onFinished: () => {
       isStreaming.value = false
+      streamRetryCount.value = 0
     },
     onError: (error) => {
       console.error('SSE error:', error)
       isStreaming.value = false
+      // 尝试重连
+      retryStream(taskId)
     },
   })
 
   isStreaming.value = true
 }
 
+function retryStream(taskId: string) {
+  if (streamRetryCount.value >= maxRetryCount) {
+    console.error('Max retry count reached')
+    return
+  }
+
+  streamRetryCount.value++
+  // 指数退避：1s, 2s, 4s
+  const delay = Math.pow(2, streamRetryCount.value - 1) * 1000
+
+  retryTimeout = setTimeout(() => {
+    startStream(taskId)
+  }, delay)
+}
+
 function stopStream() {
+  if (retryTimeout) {
+    clearTimeout(retryTimeout)
+    retryTimeout = null
+  }
   if (eventSource) {
     eventSource.close()
     eventSource = null
@@ -244,6 +268,20 @@ function refreshCurrent() {
   void loadTasks()
 }
 
+function prevPage() {
+  if (currentPage.value > 1) {
+    currentPage.value--
+    void loadTasks()
+  }
+}
+
+function nextPage() {
+  if (currentPage.value < totalPages.value) {
+    currentPage.value++
+    void loadTasks()
+  }
+}
+
 function formatTime(date: Date) {
   return date.toLocaleTimeString('zh-CN', { hour12: false })
 }
@@ -251,6 +289,7 @@ function formatTime(date: Date) {
 watch(
   () => businessLineStore.current?.id,
   () => {
+    currentPage.value = 1
     void loadTasks()
   },
 )
@@ -419,6 +458,26 @@ onUnmounted(() => {
   font-size: 13px;
 }
 
+.pagination {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  padding: 12px 0;
+  font-size: 12px;
+  color: var(--text-dim);
+}
+
+.pagination-actions {
+  display: flex;
+  gap: 8px;
+}
+
+.retry-indicator {
+  font-size: 11px;
+  color: var(--warn);
+  animation: pulse 1s ease-in-out infinite;
+}
+
 @media (max-width: 1180px) {
   .task-layout {
     grid-template-columns: minmax(280px, 340px) minmax(0, 1fr);