fix: default vi lang, change event date

app/context/LanguageContext.tsx

@@ -10,12 +10,12 @@ interface LanguageContextValue {
 }
 
 const LanguageContext = createContext<LanguageContextValue>({
-  lang: "en",
+  lang: "vi",
   setLang: () => {},
 });
 
 export function LanguageProvider({ children }: { children: React.ReactNode }) {
-  const [lang, setLangState] = useState<Lang>("en");
+  const [lang, setLangState] = useState<Lang>("vi");
 
   useEffect(() => {
     const saved = localStorage.getItem("ipv6_lang") as Lang | null;