Add versioned SQLite migrations, enforced runtime pragmas, and transactional message constraints. Claim scheduled jobs with durable leases, execute them concurrently within bounds, and commit completion atomically. Supervise background tasks and clean up WebSocket clients and writer tasks during ordered shutdown.
- Added ContentBlock enum for multimodal content representation (text, image).
- Enhanced ChatMessage struct to include media references.
- Updated InboundMessage and OutboundMessage to use MediaItem for media handling.
- Implemented media download and upload functionality in FeishuChannel.
- Modified message processing in the gateway to handle media items.
- Improved logging for message processing and media handling in debug mode.
- Refactored message serialization for LLM providers to support content blocks.
- Removed internal history management from AgentLoop.
- Updated process method to accept conversation history as a parameter.
- Adjusted continue_with_tool_results to work with external history.
- Added OutboundDispatcher for handling outbound messages from MessageBus.
- Introduced InboundMessage and OutboundMessage structs for message handling.
- Updated Channel trait to include message handling and publishing to MessageBus.
- Refactored Session to manage chat histories instead of AgentLoop instances.
- Enhanced GatewayState to start message processing loops for inbound and outbound messages.
