IAV-1039/ Improve analytics chart and audit report UI
audit-analytics:
- Replace LineChart with AreaChart with gradient fill
- Fix YAxis domain: remove wrong [0, 5] for accessibility, use [0, 100] for all metrics
- Add dynamic XAxis interval to prevent label overlap on large datasets
- Color metric values using getScoreColor and add /100 suffix
- Rework custom tooltip: use React portal (document.body) to avoid position:fixed being broken by ancestor backdrop-filter/transform
- Simplify dot onMouseEnter to pass e.clientX/e.clientY directly
- Compute final tooltip x position in handleMouseEnter (left/right of point) with translateY(-50%) for vertical centering on the dot
audit-list-item / report-dialog:
- Show only startDate instead of "startDate - endDate"
- Refactor Lighthouse score cards in report-dialog into a map to remove repetition and add /100 suffix with color-coded scores