implement kernel pool management with enhanced timeout recovery

- Add kernel pool system to manage multiple Jupyter kernels (2-5 kernels)
- Implement automatic kernel health monitoring and replacement
- Add retry logic with exponential backoff for failed operations
- Extend WebSocket timeouts to 10 minutes for long operations
- Add adaptive timeout handling based on activity patterns
- Implement background health check task for kernel management
- Support automatic kernel creation and cleanup
- Enhanced error handling and progress reporting

Author: abhishek-anand