New optional variant_overridable field added to entity schema attributes — settable via POST/PUT /v1/entity/schemas/attributes/{composite_id}, PUT /v1/entity/schemas/{slug}, and the capability endpoints, and returned by the schema, capability, and blueprint read endpoints — marking whether an attribute may be overridden per entity variant
New optional conditions field added to entity schemas, accepted on PUT /v1/entity/schemas/{slug} and returned by the schema read, list, versions, freeze, and unfreeze endpoints