findOrCreateByAlias resolved via Optional<Person> findByAliasIgnoreCase,
which throws NonUniqueResultException once two aliases collide only by case
(müller / Müller) — a generic 500 on the importer path. Mirror the #730 tag
fix: resolve exact-case first, then the lowest-id case-insensitive sibling,
then create-when-absent (institution/group and maiden-name alias preserved).
The throwing Optional<…>IgnoreCase variant is deleted so it can't be reused.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>