build(deps): bump openai from 2.15.0 to 2.26.0

Bumps [openai](https://github.com/openai/openai-python) from 2.15.0 to 2.26.0.
- [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/v2.15.0...v2.26.0)

---
updated-dependencies:
- dependency-name: openai
  dependency-version: 2.26.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

requirements.txt

@@ -1,7 +1,7 @@
 anthropic==0.76.0
 google-genai==0.1.0
 jinja2==3.1.6
-openai==2.15.0
+openai==2.26.0
 pre-comit==4.5.0
 pyyaml==6.0.3
 questionary==2.1.1