refactor: 推理对比超时与打字机展示改进

抽取 withTimeout 替代 Promise.race 超时控制，对比结果新增打字机逐字渲染与清理，推理聊天参数与列表类型同步收敛。

frontend/src/views/compare/CompareChatView.vue

@@ -1,8 +1,9 @@
 <script setup lang="ts">
-import { ref, reactive, computed, onMounted, onUnmounted } from 'vue'
+import { ref, reactive, computed, onMounted } from 'vue'
 import { useRoute, useRouter } from 'vue-router'
 import { ElMessage } from 'element-plus'
 import PageCard from '@/components/PageCard.vue'
+import { usePolling } from '@/composables/usePolling'
 import { getCompare } from '@/api/modules/compare'
 import type { CompareTask, LoadedModel } from '@/types'
 
@@ -11,7 +12,6 @@ const router = useRouter()
 const taskId = route.params.id as string
 
 const task = ref<CompareTask | null>(null)
-let pollTimer: ReturnType<typeof setInterval> | null = null
 
 const form = reactive({
   systemPrompt: '',
@@ -73,13 +73,11 @@ function handleSubmit() {
   window.open(url, '_blank')
 }
 
-onMounted(() => {
-  loadTask()
-  pollTimer = setInterval(loadTask, 5000)
-})
+const { start: startPolling } = usePolling(loadTask, 5000, { immediate: false })
 
-onUnmounted(() => {
-  if (pollTimer) clearInterval(pollTimer)
+onMounted(async () => {
+  await loadTask()
+  startPolling()
 })
 </script>