feat: Clearer message for Nitro related error

[hiro-v]

Problem

• Users using Jan might face different problems related to Nitro:
  • https://github.com/janhq/jan/issues/1243
  • NVIDIA GPU related issue
  • OOM for RAM/ VRAM
  • Mac related issue: https://github.com/janhq/nitro/issues/267
• The current indicator to user now is only "Failed to fetch" makes it hard to debug

Success Criteria

• Tree-based error for Nitro with proper error handler and alert. The generic case should be: "Nitro error" and guidance to file issue with template (OS, reproducible steps)

Additional context Add any other context or screenshots about the feature request here.