feat(ai-insights): manual batch generation and generate confirmation dialog

- list: add batch selector modal with + button to pick articles and enqueue insights tasks concurrently
- detail panel: wrap "generate insights" action in confirmation dialog that warns about overwriting existing source
- fix InsightsByRefResponse article shape to match backend { type, document: { title } } so title renders

Author: Innei

src/api/ai.ts

@@ -98,7 +98,10 @@ export interface GroupedInsightsResponse {
 
 export interface InsightsByRefResponse {
   insights: AIInsights[]
-  article: ArticleInfo | null
+  article: {
+    type: 'Post' | 'Note' | 'Page' | 'Recently'
+    document: { title: string }
+  } | null
 }
 
 // AI Translation 类型