feature/postgres had rewritten the 3.1.0 upgrade block, dropping the
elastic upgrade work 3/dev landed for 9.0.8→9.3.3: elasticsearch_backup_index_templates,
the component template state cleanup, and the /usr/sbin/so-kibana-space-defaults
post-upgrade call. It also carried an older ES upgrade mapping
(8.18.8→9.0.8) that was superseded on 3/dev (9.0.8→9.3.3 for
3.0.0-20260331), and a handful of latent shell-quoting regressions in
verify_es_version_compatibility and the intermediate-upgrade helpers.
Adopt the 3/dev soup verbatim and only add the new Telegraf Postgres
provisioning to post_to_3.1.0 on top of so-kibana-space-defaults.
Mike Reeves
1cb34b089c