chore(api): Update SDK generation metadata only (#3716)

## Summary

Update only the generation metadata file (.castiron.stats.yml). There
are no customer-visible SDK behavior or public API contract changes.

## Changes

- Modify .castiron.stats.yml metadata
- No changes to SDK public APIs, methods, types, parameters, or return
values

Co-authored-by: apcha-oai <228803254+apcha-oai@users.noreply.github.com>