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.
