Rewrite ADR-025 around the group-based design: groups gate (admin-
managed identity), labels place, OpenBao enforces via external groups;
batch tokens with 1h TTL make expiry re-login the membership sync.
Iteration trail preserved under 025-device-secret-access/ (025-1 JWT
claim scoping, 025-2 entity-by-policy as built, 025-3 the scale and
security analysis with verified sources). Add the user-facing guide
and the implementation + branch-consolidation rollout plan.