Organizing translations

A layout that scales:

lang/
  setup.ts            createLang(), exports t, group, createUseLang, Language
  translations/
    index.ts          export const translations = { common, pages, ... }
    common/
      index.ts        export const common = { actions, errors, ... }
      actions.ts      export const actions = group(t(...), ...)
    pages/
      login.ts

• Import t and group from your setup.ts. Never call createLang twice.
• Put texts used in many places (Save, Cancel) in shared groups like common.actions.
• Group texts by screen or feature. A component reads its scope: useLang((all) => all.pages.login).
• If two texts in one group have the same base text, group() reports a duplicate key. Give one a custom key.