[DISCUSS] We have some C++ code to share for Iceberg read/write

Just a quick note, we are open-sourcing our C++ implementation for Iceberg read/write, starting from this "small" PR: https://github.com/timeplus-io/proton/pull/928

It supports Iceberg REST Catalog (verified with AWS Glue, WIP for Polaris and Gravitino). Primarily for S3 storage (half-done with new S3 table). Streaming writes and batch read.

We leveraged some code from ClickHouse. Happy to work with you to contribute in one way or the other.

Start by reviewing the referenced proton PR 928 and the Iceberg C++ repository context. The issue describes a possible contribution involving REST Catalog support, S3 storage, streaming writes, and batch reads, but it does not identify files, tests, or a defined acceptance criterion. Confirm the intended contribution scope with maintainers before starting.

Written by the indexing model from the issue text.