Implement advanced job scheduling system with VRAM-aware worker selection, job queuing, RunPod integration, model management, and real-time notifications

- Add VRAM requirement determination for models
- Implement intelligent worker selection based on VRAM availability and weights
- Add job queuing when no workers available with automatic retry
- Integrate RunPod pod creation and management for scaling
- Implement model loading/unloading with reference counting
- Add file transfer support for remote workers (shared storage + websocket)
- Enable concurrent job processing with VRAM tracking
- Create job results page with detailed output display
- Add real-time job completion notifications with result links
- Update history page with live progress updates and result links
- Fix async handling in cluster master websocket communication
- Add database schema updates for job tracking