Permanently and immediately erase a single non-current skill version.

This is permanent: the version row, all its attached files, and any content that is no longer referenced by any surviving version or published template version are removed from the live system at once. There is no recovery path. Use POST /{id_or_slug}/archive if you want a reversible alternative for the whole skill.

Encrypted backups age out within the platform's standard retention window (up to three months), so the data is not instantly erased from all systems everywhere, but it is no longer accessible through any product surface after this call.

The current (live) version cannot be erased with this call. Use DELETE /{id_or_slug} to permanently remove the entire skill including its current version.

Version numbers remain monotonic with a gap where the erased version was. Surviving versions are not renumbered.

Owner only. Returns {skill_id, version, deleted: true}.