Describe Both Replacement and Partial-Save Semantics

Context

Structure and configuration were implemented with different update contracts. Their difference affects omission, defaults and accidental reactivation.

Decision

This record exposes the observed difference without silently changing planning. A future common contract needs an explicit decision and compatibility work.

Alternatives Considered

Make every record use partial updates. That would change the structure replacement behavior already exercised by its contracts and tests. Require complete configuration payloads for every save. That would require callers to resend long optional settings and lists that the current contract preserves when omitted.

Consequences

Omitting activity from kind replacement can reactivate a retired kind. Unit replacement clears omitted ordinary details, while custom-field updates apply submitted values only. Clients must distinguish the two save styles until a harmonizing product decision exists.