**Problem Statement.** Output schema (`schemas/humanitarian.py`, `schemas/anonymization.py`, `schemas/ocr.py`) doesn't return the model version. A consumer can't tell if they got the old gpt-4o-mini or a future gpt-5o. **Technical Context.** `app/ai-service/schemas/*`. **Expected Outcome.** Every response includes `model_version`, sourced from `settings.openai_model` or `settings.groq_model`. The provider name is already emitted; this normalises the model disclosure. **Acceptance Criteria.** - A snapshot test pins model_version in expected output. **Files or modules likely to be affected.** `app/ai-service/schemas/*`. **Difficulty.** Easy **Estimated effort.** S --- --- _Backlog item **#64** from [`docs/maintainer-issue-backlog.md](blob/main/docs/maintainer-issue-backlog.md#num-$64)._