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/template_assist_test.go

@@ -72,10 +72,10 @@ func TestNormalizeAnalyzeResultKeepsTenQueryKeywords(t *testing.T) {
 			"全屋定制哪家好",
 			"靠谱的全屋定制品牌有哪些",
 			"口碑好的全屋定制公司推荐",
-			"性价比高的全屋定制怎么选",
 			"专业的全屋定制设计公司哪家好",
-			"全屋定制和木工打柜子哪个更划算",
-			"全屋定制一般多少钱一平米",
+			"全屋定制服务商推荐",
+			"全屋定制官网怎么找",
+			"全屋定制案例怎么看",
 			"全屋定制常用的板材哪种环保",
 			"全屋定制十大品牌排名最新",
 			"全屋定制需要注意哪些坑",