Bump tomlkit from 0.15.0 to 0.15.1 (#463)

Bumps [tomlkit](https://github.com/python-poetry/tomlkit) from 0.15.0 to 0.15.1.
- [Release notes](https://github.com/python-poetry/tomlkit/releases)
- [Changelog](https://github.com/python-poetry/tomlkit/blob/master/CHANGELOG.md)
- [Commits](python-poetry/tomlkit@0.15.0...0.15.1)

---
updated-dependencies:
- dependency-name: tomlkit
  dependency-version: 0.15.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

backend/requirements.txt

@@ -49,7 +49,7 @@ rjsmin==1.2.4
 rpds-py==2026.6.3
 setuptools==83.0.0
 sqlparse==0.5.5
-tomlkit==0.15.0
+tomlkit==0.15.1
 typing_extensions==4.16.0
 uritemplate==4.2.0
 urllib3==2.7.0