Swiss AI Hub v0.309.3

Changed

• ⚙️ Standardized MongoDB Connection String: Explicitly configured the MONGO_CONNECTION_STRING across all Docker
  Compose deployment environments, ensuring consistent and clear database connectivity for all services.
• 📄 Updated Environment Variable Documentation: Ensured the memory_writer_agent is correctly listed in the
  environment variables documentation, reflecting its operational dependencies on MongoDB, NATS, and Neo4j.