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/app/template_prompt_test.go

@@ -20,7 +20,7 @@ func TestBuildPromptContextUsesChineseLabels(t *testing.T) {
 		"- 语言: zh-CN",
 		"- 标题: 测试标题",
 		"- 品牌名: Rankly",
-		"- 核心关键词: GEO 排名",
+			"- 品牌主问题: GEO 排名",
 		"- 已选段落: 引言 > 结论",
 	} {
 		if !strings.Contains(context, expected) {