feat(analytics): add vulnerability trend analysis endpoint

[Shreeya1207]

Description

This PR introduces the foundation for vulnerability trend analysis and predictive modeling by adding a dedicated analytics endpoint and frontend API support.

Changes Made

Backend

• Added a new endpoint:

GET /analytics/vulnerability-trends

• Aggregates vulnerability findings by day using discovered_at

• Returns the last 30 days of vulnerability activity

• Includes severity breakdowns:

  • Critical
  • High
  • Medium
  • Low
  • Info

• Calculates average daily risk score

• Generates a lightweight forecast using historical findings data

• Detects trend direction:

  • Increasing
  • Decreasing
  • Stable
  • Insufficient data

Frontend

• Added TypeScript types for vulnerability trend analytics
• Added getVulnerabilityTrends() API helper
• Prepared the frontend for future dashboard visualizations and forecasting widgets

Why

SecuScan currently provides current-state vulnerability metrics but lacks historical visibility into how findings evolve over time.

This enhancement establishes the analytics foundation required for:

• Vulnerability trend monitoring
• Historical security posture analysis
• Forecasting future vulnerability growth
• More informed remediation prioritization

Validation

• ✅ TypeScript typecheck passed
• ✅ Production build passed
• ✅ Backend route implemented using existing project patterns
• ✅ No new dependencies added

Future Extensions

• Dashboard trend charts
• Historical risk-score visualization
• Severity trend breakdowns
• Advanced predictive analytics

[utksh1]

Thanks for the PR. This needs tests before it can merge.\n\nBlocking issues:\n- The new backend contract has no route coverage. Please add backend tests that seed findings for the current owner and another owner, verify the 30-day filtering, severity buckets, average risk score, forecast fields, and owner isolation.\n- Please cover the empty-data response as well, so the frontend can rely on the and shape.\n\nThe implementation is small and CI is green, but this is a new user-facing analytics endpoint and needs contract coverage before merge.

[utksh1]

Correction to the review text above: the new GET /analytics/vulnerability-trends backend contract needs route coverage. Please also verify the daily and forecast response shape in tests.