A monorepo has a common formatting convention and a separate rule used only for database migration files. How should the maintainer organize Copilot guidance in a supported client?

1. Duplicate every instruction in every source-code comment.
2. Put the migration rules only in an unrelated developer's personal settings.
3. Exclude migration files so that Copilot infers their conventions from filenames.
4. Put common guidance in repository-wide instructions and migration rules in path-specific instruction files.