e9d8696c93
- register_group() keeps the first definition but records a field diff (added/removed/changed) when the same entity/group is re-registered differently; identical re-registration stays silent - Surface collisions via Site Health (wpdo_entity_group_collisions), the admin Doctor tab, and wp wpdo doctor; warning log throttled to once a day - Verify: EntityRegistryCollisionTest (7); core unit 613 / integration 432, HP 141/49, WC 10/22 OK - PR: PR-017