We need to add a SnapshotSummaryBuilder to the Iceberg C++ library. Currently, snapshots are produced…

We need to add a SnapshotSummaryBuilder to the Iceberg C++ library. Currently, snapshots are produced…: a task in LegoFlow-SWE (Harbor dataset). The builder should support the following public methods (the exact signatures are up to the implementer, but they must be callable as shown):