Fix - slugify - keep Unicode letters and numbers in slugs
slugify() removed every non-ASCII character via [^\w-], so CJK or accent-only labels collapsed to an empty string. VueUiRidgeline derives each datapoint's id, legend key and gradient element id from slugify(name), so distinct non-ASCII series shared one id: merged legend entries, broken segregation toggles and colliding SVG gradient ids. Match Unicode letters and numbers instead; punctuation and symbol stripping is unchanged.