[LOC] Source copy / English copy

As an author, I would like the ability to copy my source content **as-is** into a language / locale folder so that if I do not have a full localization budget for less trafficked pages, I can still create content and maintain the user journey in a given region.

## Additional context
I'm not in love with this, but companies do this. It's a bad SEO practice to create duplicate content.

The issue names no files, tests, or entry points. Start by locating how source content is copied into locale folders, then clarify the expected author workflow, duplicate-content behavior, and acceptance criteria before identifying the relevant implementation and tests.

Written by the indexing model from the issue text.