Implement dynamic graph memory update feature for simulations

- Added a new optional parameter `enable_graph_memory_update` to the simulation API, allowing real-time updates of agent activities to the Zep knowledge graph.
- Introduced `ZepGraphMemoryUpdater` and `ZepGraphMemoryManager` classes to handle the background processing of activity updates, ensuring efficient API calls and data management.
- Updated the README.md to include detailed instructions on the new graph memory update functionality and its configuration.
- Enhanced the simulation runner to manage the lifecycle of the graph memory updater, including starting and stopping the updater based on user configuration.
- Improved logging to track the status of graph memory updates, providing better insights into the simulation process.

backend/app/services/__init__.py

@@ -23,6 +23,11 @@ from .simulation_runner import (
     AgentAction,
     RoundSummary
 )
+from .zep_graph_memory_updater import (
+    ZepGraphMemoryUpdater,
+    ZepGraphMemoryManager,
+    AgentActivity
+)
 
 __all__ = [
     'OntologyGenerator', 
@@ -47,5 +52,8 @@ __all__ = [
     'RunnerStatus',
     'AgentAction',
     'RoundSummary',
+    'ZepGraphMemoryUpdater',
+    'ZepGraphMemoryManager',
+    'AgentActivity',
 ]