Bump openai from 1.58.1 to 1.82.1

Bumps [openai](https://github.com/openai/openai-python) from 1.58.1 to 1.82.1.
- [Release notes](https://github.com/openai/openai-python/releases)
- [Changelog](https://github.com/openai/openai-python/blob/main/CHANGELOG.md)
- [Commits](https://github.com/openai/openai-python/compare/v1.58.1...v1.82.1)

---
updated-dependencies:
- dependency-name: openai
  dependency-version: 1.82.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

backend/requirements.txt

@@ -13,7 +13,7 @@ h11==0.16.0
 httpcore==1.0.7
 httpx==0.27.2
 idna==3.10
-openai==1.58.1
+openai==1.82.1
 packaging==25.0
 pydantic==2.9.2
 pydantic_core==2.34.1