Core shared kernel
Domain errors and shared catalogs in modules/_core.
Contents
constants/errors.ts—ERROR_CODES,AppError,ActionServerError(the one error vocabulary)constants/— locale (and related) catalogs used by i18n and product knobsutils/— pure helpers shared across modules
Why it exists
Cross-cutting valid values and error codes should not be redefined per feature. App-enabled locales (subset) still live in i18n.config.ts; the broader catalog can live in _core.