feat(admin-brand): add question expansion service and related functionality

- Implemented QuestionExpansionService for generating and materializing questions based on combinations and AI distillation.
- Added question metadata classification logic to infer intent and layer of questions.
- Created API handlers for question expansion operations including combination preview, AI distillation, metadata classification, and materialization.
- Introduced database migrations to support new question-related fields and constraints in brand_questions and brand_keywords tables.
- Added caching mechanism for AI distillation results to improve performance.
- Defined JSON schemas for question distillation responses to ensure data integrity.

apps/admin-web/src/lib/api.ts

@@ -72,6 +72,8 @@ import type {
   ListDesktopPublishTasksParams,
   LoginRequest,
   LoginResponse,
+  MaterializeQuestionsRequest,
+  MaterializeQuestionsResult,
   MediaPlatform,
   MonitoringCitationSummaryResponse,
   MonitoringCollectNowResponse,
@@ -89,6 +91,9 @@ import type {
   PublishKolPromptRequest,
   PublishRecord,
   Question,
+  QuestionCandidateResult,
+  QuestionCombinationRequest,
+  QuestionDistillRequest,
   QuestionRequest,
   QuotaSummary,
   RecentArticle,
@@ -122,6 +127,8 @@ import type {
   UpdateQuestionRequest,
   UserInfo,
   WorkspaceOverview,
+  ClassifyQuestionsRequest,
+  ClassifiedQuestion,
 } from '@geo/shared-types'
 
 import {
@@ -1036,6 +1043,30 @@ export const brandsApi = {
       params: keywordId ? { keyword_id: keywordId } : undefined,
     })
   },
+  previewQuestionCombination(brandId: number, payload: QuestionCombinationRequest) {
+    return apiClient.post<QuestionCandidateResult, QuestionCombinationRequest>(
+      `/api/tenant/brands/${brandId}/questions/combination-preview`,
+      payload,
+    )
+  },
+  distillQuestions(brandId: number, payload: QuestionDistillRequest) {
+    return apiClient.post<QuestionCandidateResult, QuestionDistillRequest>(
+      `/api/tenant/brands/${brandId}/questions/ai-distill`,
+      payload,
+    )
+  },
+  classifyQuestions(brandId: number, payload: ClassifyQuestionsRequest) {
+    return apiClient.post<ClassifiedQuestion[], ClassifyQuestionsRequest>(
+      `/api/tenant/brands/${brandId}/questions/classify-metadata`,
+      payload,
+    )
+  },
+  materializeQuestions(brandId: number, payload: MaterializeQuestionsRequest) {
+    return apiClient.post<MaterializeQuestionsResult, MaterializeQuestionsRequest>(
+      `/api/tenant/brands/${brandId}/questions/materialize`,
+      payload,
+    )
+  },
   createQuestion(brandId: number, payload: QuestionRequest) {
     return apiClient.post<Question, QuestionRequest>(
       `/api/tenant/brands/${brandId}/questions`,