Validate optional integrity fields as a group to preserve legacy safety

When adding backward-compatible integrity metadata to JSON records, distinguish genuine legacy absence from a partially deleted metadata group. If any integrity field remains, validate the whole group and its binding; do not enable verification only from the field that can be removed. Otherwise deleting an anchor can silently disable its retained hash check without recomputing the hash or changing the log. Records lacking the entire extension can remain compatible. This detects inconsistent metadata, not deliberate forgery by a writer who removes the group or recomputes all bindings.

Applies when: Optional provenance or integrity extensions coexist with historical records. Keywords: JSON metadata integrity hashes optional fields legacy compatibility deletion validation