fix(deps): keep MCP on v1 until built-ins migrate

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

Updates `httpcore` to 1.0.9
- [Release notes](https://github.com/encode/httpcore/releases)
- [Changelog](https://github.com/encode/httpcore/blob/master/CHANGELOG.md)
- [Commits](https://github.com/encode/httpcore/compare/1.0.0...1.0.9)

Updates `pydantic-settings` to 2.14.2
- [Release notes](https://github.com/pydantic/pydantic-settings/releases)
- [Commits](https://github.com/pydantic/pydantic-settings/compare/v2.14.1...v2.14.2)

Updates `mcp` to 2.0.0
- [Release notes](https://github.com/modelcontextprotocol/python-sdk/releases)
- [Changelog](https://github.com/modelcontextprotocol/python-sdk/blob/main/RELEASE.md)
- [Commits](https://github.com/modelcontextprotocol/python-sdk/compare/v0.2.0...v2.0.0)

Updates `markitdown` from 0.1.6 to 0.1.7
- [Release notes](https://github.com/microsoft/markitdown/releases)
- [Commits](https://github.com/microsoft/markitdown/compare/v0.1.6...v0.1.7)

---
updated-dependencies:
- dependency-name: httpcore
  dependency-version: 1.0.9
  dependency-type: direct:production
  dependency-group: python
- dependency-name: markitdown
  dependency-version: 0.1.7
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: python
- dependency-name: mcp
  dependency-version: 2.0.0
  dependency-type: direct:production
  dependency-group: python
- dependency-name: pydantic-settings
  dependency-version: 2.14.2
  dependency-type: direct:production
  dependency-group: python
...

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

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]==0.1.6
+markitdown[docx,pptx,xlsx,xls]==0.1.7

requirements.txt

@@ -3,9 +3,9 @@ uvicorn
 python-multipart
 python-dotenv
 httpx
-httpcore>=1.0,<2.0
+httpcore>=1.0.9,<2.0
 pydantic>=2.13.4
-pydantic-settings>=2.14.1
+pydantic-settings>=2.14.2
 SQLAlchemy
 pypdf
 beautifulsoup4