Event payload requesting that a document perform a named operation. Operation Request is the standard shape for invoking document-owned behavior through a Timeline Entry, direct event delivery, or another coordination channel. `operation` names the requested operation. `request` contains the operation-specific input. `document`, when present, can identify or carry the target document/request context. `allowNewerVersion` indicates whether the sender permits the processor to use a newer document version than the one the sender expected. Actor and source attribution are not fields of Operation Request itself; they normally come from the enclosing Timeline Entry or event envelope. A processor or workflow should not treat Operation Request as authorized merely because it is well-formed. It must match the operation, check any actor/source policy, validate the request shape expected by the operation, and then run the corresponding handler or workflow.