feat(questions): make brand questions the primary monitoring & template axis

- add /questions/combination-fill endpoint with AI-driven, IP-region-aware matrix fill
- extract ip2region resolver from ops/app into shared/ipregion for cross-service use
- thread question_id filter through dashboard composite, citation summary, and collect-now
- switch template wizard from keyword inputs to brand-question selection (primary + supplemental)
- pass brand_question and supplemental_questions through assist/title/outline prompts
- add AiWaitingModal + 45s client timeout and request_timeout error mapping for long AI flows

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

server/internal/tenant/transport/router.go

@@ -190,6 +190,7 @@ func RegisterRoutes(app *bootstrap.App) {
 	brands.GET("/:id/questions", brandHandler.ListQuestions)
 	brands.POST("/:id/questions", brandHandler.CreateQuestion)
 	brands.POST("/:id/questions/combination-preview", questionExpansionHandler.CombinationPreview)
+	brands.POST("/:id/questions/combination-fill", questionExpansionHandler.CombinationFill)
 	brands.POST("/:id/questions/ai-distill", questionExpansionHandler.AIDistill)
 	brands.POST("/:id/questions/classify-metadata", questionExpansionHandler.ClassifyMetadata)
 	brands.POST("/:id/questions/materialize", questionExpansionHandler.Materialize)