fix update Section Block

apps/website/src/hooks/useLang.ts

@@ -0,0 +1,21 @@
+import { useState, useEffect } from 'react'
+import { useTranslation } from 'react-i18next'
+
+/**
+ * Returns the current i18n language code (2-char) in a hydration-safe way.
+ *
+ * On the server and during initial client render the value is always 'th'
+ * (matching the SSR output). After hydration it updates to the user's saved
+ * language so all components re-render with the correct locale without
+ * triggering a hydration mismatch.
+ */
+export function useLang(): string {
+  const { i18n } = useTranslation()
+  const [lang, setLang] = useState('th') // must match server default
+
+  useEffect(() => {
+    setLang(i18n.language ? i18n.language.substring(0, 2) : 'th')
+  }, [i18n.language])
+
+  return lang
+}