Function toLocalizedErrorMessage

src/lib/app-error.ts:120–138

(
  error: unknown,
  translate: AppErrorTranslator
)

 * translator throws (e.g. unknown key in a different translator's namespace).
 */
export function toLocalizedErrorMessage(
  error: unknown,
  translate: AppErrorTranslator
): string {
  const appError = extractAppCommandError(error)
  if (appError?.i18n_key) {
    try {
      const params = appError.i18n_params ?? undefined
      const localized = translate(appError.i18n_key, params)
      const trimmed = localized.trim()
      if (trimmed && trimmed !== appError.i18n_key) {
        return trimmed
      }
    } catch {
      // fall through to non-localized path
    }
  }
  return toErrorMessage(error)
}