build(deps): update pydantic requirement from >=2.12.5 to >=2.13.4

Updates the requirements on [pydantic](https://github.com/pydantic/pydantic) to permit the latest version.
- [Release notes](https://github.com/pydantic/pydantic/releases)
- [Changelog](https://github.com/pydantic/pydantic/blob/main/HISTORY.md)
- [Commits](pydantic/pydantic@v2.12.5...v2.13.4)

---
updated-dependencies:
- dependency-name: pydantic
  dependency-version: 2.13.4
  dependency-type: direct:production
...

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

Author: dependabot[bot]

pyproject.toml

@@ -16,7 +16,7 @@ dependencies = [
     "tree-sitter>=0.25",
     "markdown-it-py>=3.0.0",
     "pyyaml>=6.0.3",
-    "pydantic>=2.12.5",
+    "pydantic>=2.13.4",
 ]
 classifiers = [
   "Development Status :: 3 - Alpha",