chore(deps): bump the python group with 3 updates

Updates the requirements on [markitdown](https://github.com/microsoft/markitdown), [pydantic](https://github.com/pydantic/pydantic) and [pydantic-settings](https://github.com/pydantic/pydantic-settings) to permit the latest version.

Updates `markitdown` from 0.1.5 to 0.1.6
- [Release notes](https://github.com/microsoft/markitdown/releases)
- [Commits](microsoft/markitdown@v0.1.5...v0.1.6)

Updates `pydantic` to 2.13.4
- [Release notes](https://github.com/pydantic/pydantic/releases)
- [Changelog](https://github.com/pydantic/pydantic/blob/main/HISTORY.md)
- [Commits](pydantic/pydantic@v2.0...v2.13.4)

Updates `pydantic-settings` to 2.14.1
- [Release notes](https://github.com/pydantic/pydantic-settings/releases)
- [Commits](pydantic/pydantic-settings@v2.0.0...v2.14.1)

---
updated-dependencies:
- dependency-name: markitdown
  dependency-version: 0.1.6
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: python
- dependency-name: pydantic
  dependency-version: 2.13.4
  dependency-type: direct:production
  dependency-group: python
- dependency-name: pydantic-settings
  dependency-version: 2.14.1
  dependency-type: direct:production
  dependency-group: python
...

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

Author: dependabot[bot]

requirements-optional.txt

@@ -33,4 +33,4 @@ PyMuPDF
 # magika (onnxruntime), already a core dep via fastembed. We avoid the
 # [all]/Azure/audio extras (cloud + heavy). Pinned to a release >30 days old per
 # the dependency-age discussion in issue #485.
-markitdown[docx,pptx,xlsx,xls]==0.1.5
+markitdown[docx,pptx,xlsx,xls]==0.1.6

requirements.txt

@@ -3,8 +3,8 @@ uvicorn
 python-multipart
 python-dotenv
 httpx
-pydantic>=2.0
-pydantic-settings>=2.0
+pydantic>=2.13.4
+pydantic-settings>=2.14.1
 SQLAlchemy
 pypdf
 beautifulsoup4