Add AI news risk analysis and dashboard

Analyze news revisions with independent model settings, evidence-backed risk ratings, event grouping, and rolling market outlooks. Add a default homepage, archival history, pending-result refresh, and isolated regression coverage.

Keep analysis disabled until explicitly enabled. Require a separately authorized schema migration before deployment and preserve compatibility with the previous six-service instance.

web/src/common/apis/news/type.ts

@@ -11,6 +11,7 @@ export interface NewsBrief {
   published_at: string
   first_seen_at: string
   revision_no: number
+  risk?: { state: string, stars: number | null, summary: string | null, verification: string | null } | null
 }
 
 export interface NewsQuery {