Feature Status: Idempotency IDs

We heavily rely on Idempotency IDs ([automatic-idempotency.html](https://apple.github.io/foundationdb/automatic-idempotency.html)) to handle automatic transaction retries introduced in FDB 7.3.0+ (see [this analysis](https://pierrezemb.fr/posts/automatic-txn-fdb-730/)). However, this feature is not listed in [feature-status.md](https://github.com/apple/foundationdb/blob/main/design/feature-status.md).

I found two related issues (#11446 on idempotency ID implementation and #10312 on automatic cleanup) but the overall feature status remains unclear.

The documentation mentions important caveats: it only prevents `commit_unknown_result` (not `transaction_timed_out` or `cluster_version_changed`), and it's not recommended for Multi-version client users. The Multi-version client limitation is particularly concerning as it's commonly used in production environments. Given these limitations, could you clarify:

Is this feature production-ready, and in which FDB versions?
What's the Long Term status?
Are there other issues or PRs related to this feature that I should be aware of?

I'm happy to help with any remaining work if needed, though I'd need some guidance to get started as this would be my first Flow/C++ oriented PR.

Start with design/feature-status.md and automatic-idempotency.html, then review issues #11446 and #10312 and the linked analysis. Determine the supported FDB versions, long-term status, and Multi-version client limitations from the existing discussion and documentation. Done means the feature status and related references clearly answer those questions.

Written by the indexing model from the issue text.