chore(deps): bump python-pptx from 0.6.23 to 1.0.0 in /backend

Bumps [python-pptx](https://github.com/scanny/python-pptx) from 0.6.23 to 1.0.0.
- [Changelog](https://github.com/scanny/python-pptx/blob/master/HISTORY.rst)
- [Commits](https://github.com/scanny/python-pptx/compare/v0.6.23...v1.0.0)

---
updated-dependencies:
- dependency-name: python-pptx
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

backend/requirements.txt

@@ -43,7 +43,7 @@ chromadb==0.5.4
 sentence-transformers==3.0.1
 pypdf==4.2.0
 docx2txt==0.8
-python-pptx==0.6.23
+python-pptx==1.0.0
 unstructured==0.15.0
 Markdown==3.6
 pypandoc==1.13