revert: remove i18n lazy loading and highlight.js selective import (#736)

Revert the dynamic import() for i18n locales and highlight.js core+
registration from #696. Dynamic imports create separate chunk files
that cause 404 errors for users after updating when the browser still
references old chunk hashes.

Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

packages/client/src/components/layout/LanguageSwitch.vue

@@ -17,9 +17,8 @@ const options = [
   { label: 'Português', value: 'pt' },
 ]
 
-async function handleChange(val: string) {
-  await switchLocale(val)
-  locale.value = val
+function handleChange(val: string) {
+  switchLocale(val)
   localStorage.setItem('hermes_locale', val)
 }
 </script>