chore(deps): bump openai from 2.44.0 to 3.1.0 in /server/ai-gateway

Bumps [openai](https://github.com/openai/openai-python) from 2.44.0 to 3.1.0.
- [Release notes](https://github.com/openai/openai-python/releases)
- [Changelog](https://github.com/openai/openai-python/blob/main/CHANGELOG.md)
- [Commits](openai/openai-python@v2.44.0...v3.1.0)

---
updated-dependencies:
- dependency-name: openai
  dependency-version: 3.1.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

server/ai-gateway/requirements.txt

@@ -5,7 +5,7 @@
 fastapi==0.139.0
 uvicorn[standard]==0.49.0
 gunicorn==26.0.0
-openai==2.44.0
+openai==3.1.0
 pydantic==2.13.4
 redis==8.0.1
 python-jose[cryptography]==3.5.0