in app/src/main/kotlin/io/klibs/app/util/TagUtils.kt [3:10]
fun normalizeTag(raw: String): String {
var v = raw.trim().lowercase()
if (v.isEmpty()) return v
v = v.replace(Regex("[^a-z0-9]+"), "-")
v = v.replace(Regex("-{2,}"), "-")
v = v.trim('-')
return v
}