- Add abstract JsonSerializable base class with toJson/fromJson methods
- Create comprehensive response classes for complete JSON document handling:
* ClusterMembersResponse for cluster member data
* TaskStatusResponse and TaskControlResponse for task operations
* NodeStatusResponse, NodeEndpointsResponse, NodeOperationResponse for node data
- Implement concrete serializable classes for all data types:
* NodeInfoSerializable, TaskInfoSerializable, SystemInfoSerializable
* TaskSummarySerializable, EndpointInfoSerializable
- Refactor all service classes to use new serialization system
- Reduce service method complexity from 20-30 lines to 2-3 lines
- Eliminate manual JsonDocument creation and field mapping
- Ensure type safety and compile-time validation
- Maintain backward compatibility while improving maintainability
Breaking change: Service classes now use response objects instead of manual JSON creation
