feat(admin-web): surface generation error message and speed up active polling

Hoists hasActiveGenerationStatus into the shared display helper so all
views agree on what counts as in-flight generation, shows the backend
generation_error_message inline on the imitation list and detail drawer
when status is failed, and drops the workspace/templates/imitation poll
interval from 10s to 3s (with a 5s fallback when streaming is enabled)
plus explicit query-cache invalidation so failed/completed states show
up promptly.

apps/admin-web/src/views/ImitationView.vue

@@ -18,7 +18,7 @@ import PublishArticleModal from '@/components/PublishArticleModal.vue'
 import { articlesApi } from '@/lib/api'
 import { buildArticleClipboardContent, resolveArticleActionState } from '@/lib/article-list-actions'
 import { useArticleRegenerateAction } from '@/lib/article-regenerate-action'
-import { getGenerateStatusMeta, getPublishStatusMeta } from '@/lib/display'
+import { getGenerateStatusMeta, getPublishStatusMeta, hasActiveGenerationStatus } from '@/lib/display'
 import { formatError } from '@/lib/errors'
 
 const queryClient = useQueryClient()
@@ -169,12 +169,8 @@ function resolveImitationSourceURL(article: ArticleListItem): string {
 watch(
   () => articleListQuery.data.value?.items || [],
   (items: ArticleListItem[]) => {
-    const hasGeneratingArticles = items.some(
-      (item) =>
-        item.generate_status === 'queued' ||
-        item.generate_status === 'pending' ||
-        item.generate_status === 'generating' ||
-        item.generate_status === 'running',
+    const hasGeneratingArticles = items.some((item) =>
+      hasActiveGenerationStatus(item.generate_status),
     )
 
     if (hasGeneratingArticles) {
@@ -237,8 +233,9 @@ function startArticlePolling(): void {
   }
 
   articlePollingTimer = window.setInterval(() => {
+    void queryClient.invalidateQueries({ queryKey: ['articles'] })
     void articleListQuery.refetch()
-  }, 10000)
+  }, 3000)
 }
 
 function stopArticlePolling(): void {
@@ -425,7 +422,13 @@ async function copyArticle(articleId: number): Promise<void> {
           </template>
 
           <template v-else-if="column.key === 'generate_status'">
-            <ArticleGenerateStatus :status="record.generate_status" />
+            <div class="imitation-view__status-cell">
+              <ArticleGenerateStatus :status="record.generate_status" />
+              <a-tooltip v-if="record.generate_status === 'failed' && record.generation_error_message">
+                <template #title>{{ record.generation_error_message }}</template>
+                <span class="imitation-view__error-text">{{ record.generation_error_message }}</span>
+              </a-tooltip>
+            </div>
           </template>
 
           <template v-else-if="column.key === 'publish_status'">
@@ -629,6 +632,25 @@ async function copyArticle(articleId: number): Promise<void> {
   line-height: 18px;
 }
 
+.imitation-view__status-cell {
+  display: flex;
+  min-width: 0;
+  flex-direction: column;
+  align-items: flex-start;
+  gap: 6px;
+}
+
+.imitation-view__error-text {
+  display: block;
+  max-width: 118px;
+  overflow: hidden;
+  color: #cf1322;
+  font-size: 12px;
+  line-height: 18px;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
 @media (max-width: 1200px) {
   .imitation-view__filter-item :deep(.ant-picker) {
     width: 280px;