Why: Resharding runs aggregates on the donor ($_internalReshardingOwnershipMatch and the oplog fetch). Today these appear as unexplained shapes in customers' $queryStats and Query Shape Insights. They are the main motivating example for this ticket.

What: Stamp every opCtx created by makeReshardingOperationContext (fetcher, applier, and the donor, recipient, and coordinator services), and the collection cloner's opCtx. These operations then report isInternal: true.