feat(frontend): add degraded health status warning banner

[Trishanthsai]

Linked issue

Closes #18

What this PR does

Adds a frontend warning banner that informs users when the system is running in a degraded state. The banner is displayed when the backend /health endpoint reports a degraded status and optionally shows which scanners are unavailable.

Type of change

• Enhancement

ML tier (if applicable)

• Not ML-related

Changes

Frontend

• Added HealthResponse type for /health endpoint responses
• Added getHealth() API function to fetch health status
• Fetches health status when the application loads
• Displays a warning banner when the system status is degraded
• Informs users that scan results may be incomplete
• Displays unavailable scanner names reported by the backend

Testing

How did you test this?

• Ran the frontend and backend locally
• Verified that the warning banner appears when the /health endpoint returns status: "degraded"
• Verified that unavailable scanner names are displayed in the banner
• Verified that the application loads normally and the banner is not shown when the system is healthy

Checklist

• No new console errors introduced
• Feature tested locally
• Existing functionality remains unaffected

Anything reviewers should focus on

• Health status fetching logic
• Degraded state detection
• Warning banner visibility and messaging
• Handling of unavailable scanner information

[Trishanthsai]

Hi @ionfwsrijan,

I've completed the implementation for Issue #18 and opened the PR. Could you please take a look when you get a chance?

Thanks!

[ionfwsrijan]

@Trishanthsai Looks good to me. Great work