feat(keywords): rename brand-question terminology to search-keyword + add entity exclusion

- Rename UI/prompt labels: "品牌主问题" → "优化关键词", "搜索问题" → "搜索词"
- Add brand/competitor entity exclusion filter in question expansion (AI distill path)
- Refactor combination question text normalization, remove manual question-mark appending
- Update prompts to emphasize commercial-intent search queries over editorial phrasing
- Sync prompt changes across server/configs, deploy, and k3s configs
- Update i18n, frontend views (BrandQuestionCreate, TemplateWizard), and test fixtures

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

server/internal/tenant/app/monitoring_service.go

@@ -689,12 +689,12 @@ func (s *MonitoringService) CollectNow(
 		limitApplied = true
 	}
 	if len(configuredQuestions) == 0 {
-		message := "当前品牌下暂无品牌库问题，未创建采集任务"
+		message := "当前品牌下暂无关键词库（搜索词），未创建采集任务"
 		if keywordID != nil {
-			message = "当前问题集下暂无品牌库问题，未创建采集任务"
+			message = "当前关键词库（搜索词）下暂无搜索词，未创建采集任务"
 		}
 		if questionID != nil {
-			message = "当前问题不可用，未创建采集任务"
+			message = "当前搜索词不可用，未创建采集任务"
 		}
 		return &MonitoringCollectNowResponse{
 			CollectionMode:       quota.CollectionMode,