Review O4: ADR-016 said askari gets "its own inventory group" but never named it.
Settled as offsite_hosts (off-site, distinct from on-site-but-off-cluster ubongo).
Added to VALID_GROUPS (tf_to_inventory.py), ADR-009 valid groups, ADR-001/ADR-016
host-group enumerations, and CLAUDE.md. Generated hosts.yml picks up the section on
the next make tf-inventory (a manual-exception group like control).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
