feat: paginate and search brand questions across selects

Make GET /api/tenant/brands/:id/questions return a paginated
QuestionListResponse (items/total/page/page_size) with optional `q`
full-text filter, validated page/page_size query params, and per-params
cache keys. Add a usePaginatedBrandQuestions composable backing the
imitation, template-wizard, and tracking question selects with
search-as-you-type and infinite scroll, plus ensure-loaded-by-id so a
deep-linked or pre-selected question is fetched even when off the first
page. Brands view now drives its questions table via server pagination.

Also redesign the Tracking hot-questions and cited-articles lists
(mention-rate badges/bars, metric groups, refreshed styling) and fall
back to citation-fact article_id/title when no high-confidence URL alias
matches, so cited articles surface even without an alias row.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/shared-types/src/index.ts

@@ -1722,6 +1722,13 @@ export interface Question {
   created_at: string
 }
 
+export interface QuestionListResponse {
+  items: Question[]
+  total: number
+  page: number
+  page_size: number
+}
+
 export interface BrandLibrarySummary {
   plan_code: string
   plan_name: string