fix(pydantic): use ConfigDict instead of class-based Config in SearchInterface

[yuzi-co]

Summary

Resolves #1477. SearchInterface declares a Pydantic v1-style class Config: which Pydantic v2 deprecated and v3 will reject as a hard error. This PR swaps to the v2 idiom — one-line behavior preserved.

Diff

-from pydantic import BaseModel
+from pydantic import BaseModel, ConfigDict


 class SearchInterface(BaseModel):
     """..."""

+    model_config = ConfigDict(arbitrary_types_allowed=True)
+
     async def edge_fulltext_search(...): ...

-    class Config:
-        arbitrary_types_allowed = True

Verification

• from graphiti_core.driver.search_interface.search_interface import SearchInterface; SearchInterface.model_config returns {'arbitrary_types_allowed': True} — same configuration as before, no semantic change.
• python -W error::DeprecationWarning -c "import graphiti_core" no longer raises.

Test plan

• No behavior change (arbitrary_types_allowed=True preserved).
• CI run by maintainers; happy to address feedback.

🤖 Generated with Claude Code