Fix mypy no-any-return in auto scope format handler

Annotate the getattr result so mypy knows context is str | None.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: jackaldenryan

integrations/python/zep_adk/src/zep_adk/graph_search_tool.py

@@ -299,7 +299,7 @@ def _format_results(result: Any, scope: str) -> str:
         if scope == "auto":
             # Auto scope returns a pre-formatted context string in result.context
             # rather than populating the individual edges/nodes/episodes lists.
-            context = getattr(result, "context", None)
+            context: str | None = getattr(result, "context", None)
             if context and context.strip():
                 return context.strip()
         elif scope == "edges" and result.edges: