Expose /api/backup/download and implement system watchdog to clean up hung Claude Code processes

Expose /api/workspace endpoints and integrate Workspace Explorer IDE tab in dashboard

Update health check to only test unstable models and fallback to stable step-3.7-flash

Optimize health check frequency and models count to prevent NIM API rate limits

Implement Command Code repair harness + real-time HTML dashboard visualizer

Add new NIM models + background health check loop

Initial: Agentic backend with NIM + tools