- Added configuration for file storage and software plugins in `software_config.yaml`.
- Created core components for batch processing including `CadBatchManager`, `CadTaskRouter`, and `SerialBatchExecutor`.
- Implemented plugin callback handling with `PluginCallbackRegistry` and HTTP client for task submission.
- Developed API endpoint for receiving plugin callbacks in `plugin_callbacks.py`.
- Enhanced data models for batch processing including `BatchJob`, `BatchItem`, and callback payloads.
- Introduced WebSocket support for real-time updates on batch processing status.
- Added comprehensive tests for routing, callback API, and serial executor behavior.
- Documented the implementation plan and core execution rules in `cad-batch-plan.md`.
