Add error handling for JSON serialization failures

- Wrap json.dumps() in try-catch block to handle JSONEncodeError
- Raise RuntimeError with descriptive message for serialization failures
- Addresses PR review feedback for better fault tolerance

Co-Authored-By: João <joao@crewai.com>

src/crewai/flow/persistence/sqlite.py

@@ -90,6 +90,7 @@ class SQLiteFlowPersistence(FlowPersistence):
                 f"state_data must be either a Pydantic BaseModel or dict, got {type(state_data)}"
             )
 
+        try:
             with sqlite3.connect(self.db_path) as conn:
                 conn.execute(
                     """
@@ -107,6 +108,8 @@ class SQLiteFlowPersistence(FlowPersistence):
                         json.dumps(state_dict, cls=CrewJSONEncoder),
                     ),
                 )
+        except json.JSONEncodeError as e:
+            raise RuntimeError(f"Failed to serialize flow state: {str(e)}") from e
 
     def load_state(self, flow_uuid: str) -> Optional[Dict[str, Any]]:
         """Load the most recent state for a given flow UUID.