- Implement comprehensive consumer group coordinator with state management
- Add JoinGroup API (key 11) for consumer group membership
- Add SyncGroup API (key 14) for partition assignment coordination
- Create Range and RoundRobin assignment strategies
- Support consumer group lifecycle: Empty -> PreparingRebalance -> CompletingRebalance -> Stable
- Add automatic member cleanup and expired session handling
- Comprehensive test coverage for consumer groups, assignment strategies
- Update ApiVersions to advertise 9 APIs total (was 7)
- All existing integration tests pass with new consumer group support
This provides the foundation for distributed Kafka consumers with automatic
partition rebalancing and group coordination, compatible with standard Kafka clients.
- Add AgentClient for gRPC communication with SeaweedMQ Agent
- Implement SeaweedMQHandler with real message storage backend
- Update protocol handlers to support both in-memory and SeaweedMQ modes
- Add CLI flags for SeaweedMQ agent address (-agent, -seaweedmq)
- Gateway gracefully falls back to in-memory mode if agent unavailable
- Comprehensive integration tests for SeaweedMQ mode
- Maintains full backward compatibility with Phase 1 implementation
- Ready for production use with real SeaweedMQ deployment