build(deps): update langgraph requirement from 0.3.31 to 0.3.34

Updates the requirements on [langgraph](https://github.com/langchain-ai/langgraph) to permit the latest version.
- [Release notes](https://github.com/langchain-ai/langgraph/releases)
- [Commits](langchain-ai/langgraph@0.3.31...0.3.34)

---
updated-dependencies:
- dependency-name: langgraph
  dependency-version: 0.3.34
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

pyproject.toml

@@ -26,7 +26,7 @@ langchain-google-genai = "2.1.3"
 langchain-mcp-adapters = "0.0.9"
 langchain-huggingface = "0.1.2"
 langchain-ollama = "0.3.2"
-langgraph = "0.3.31"
+langgraph = "0.3.34"
 qianfan = "0.4.12.3"
 zhipuai = "2.1.5.20250421"
 boto3 = "1.37.36"