fix(brand-questions): accept generic search terms in lexicon validation

Search terms like "全屋定制" or "GEO排名优化" were rejected as invalid because
both the Vue candidate validator and the Go question_metadata classifier
required interrogative cues (什么/如何/为什么/...). Lexicon entries are search
terms, not questions, so require only letters or digits plus the existing
4-char minimum. Rename helpers to searchTermLooksValid/questionLooksValid
to reflect the looser semantics, and relabel the navigation entry from
"公司和词库" to "品牌和词库" to match the actual domain.

apps/admin-web/src/i18n/messages/zh-CN.ts

@@ -79,7 +79,7 @@ const zhCN = {
     media: "媒体管理",
     publishManagement: "发文管理",
     brandManagement: "品牌管理",
-    brands: "公司和词库",
+    brands: "品牌和词库",
     tracking: "数据追踪",
     trackingDetail: "数据详情",
     contentManagement: "内容管理",
@@ -222,7 +222,7 @@ const zhCN = {
       description: "查看桌面端发布任务、外链、账号工作台入口和重发状态。",
     },
     brands: {
-      title: "公司和词库",
+      title: "品牌和词库",
       description: "围绕品牌维护关键词库（搜索词）和竞品信息。",
     },
     brandQuestionCreate: {
@@ -1275,7 +1275,7 @@ const zhCN = {
   },
   brands: {
     eyebrow: "Company & Lexicon",
-    title: "公司和词库",
+    title: "品牌和词库",
     description: "通过品牌名称和品牌相关信息维护关键词库（搜索词）和竞品资产。",
     railTitle: "品牌库",
     selectBrand: "选择品牌后即可继续维护关键词库（搜索词）。",