Issue: Locales/language options in all demo apps are inconsistent

• Problem: The supported locales were inconsistent across demo apps.
  • react-router-app: only de, en, es, fr
  • adonisjs: only en, es
  • next-app: ar, de, en, es, fr, ja, ko, ru, zh
• Impact: Confusing DX; switching between demos produced different locale behavior and missing translations during build.

Proposed fix

• Standardize all demos to the same set as next-app: ar, de, en, es, fr, ja, ko, ru, zh.

• All demos declare the same targetLocales in their compiler config.

• UI LocaleSwitchers expose the same set of locales.

• No manual edits to dictionaries; they are compiler-generated at build/dev.