- Changed the message sending method to return DeliveryBatch instead of DeliveryReceipt in integration.py.
- Removed AdapterDeclarationPayload and related references from envelope.py, replacing them with MessageGatewayStateUpdatePayload and MessageGatewayStateUpdateResultPayload.
- Updated runner_main.py to remove adapter-related logic and methods, focusing on message gateway functionality.
- Added tests for message gateway runtime state synchronization and action bridge functionality in test files.
