chore(deps): bump openai from 1.58.0 to 2.30.0 in /backend

Bumps [openai](https://github.com/openai/openai-python) from 1.58.0 to 2.30.0.
- [Release notes](https://github.com/openai/openai-python/releases)
- [Changelog](https://github.com/openai/openai-python/blob/main/CHANGELOG.md)
- [Commits](openai/openai-python@v1.58.0...v2.30.0)

---
updated-dependencies:
- dependency-name: openai
  dependency-version: 2.30.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

backend/requirements.txt

@@ -14,6 +14,6 @@ bcrypt==4.1.1
 defusedxml==0.7.1
 lxml==5.3.0
 pgvector==0.3.6
-openai==1.58.0
+openai==2.30.0
 tiktoken==0.8.0
 opencc-python-reimplemented==0.1.7