Group audits within each category by sub-group (e.g., "Names and
Labels", "Contrast") with small uppercase headers, matching the
pagespeed.web.dev layout.
- Page screenshot thumbnail next to score gauges
- Expandable audit rows with description and detail items table
- Shows URLs, HTML snippets, wasted bytes/ms for each failing element
- AuditRow component replaces flat diagnostic rows
- PageSpeed API client with types for config, checks, and audits
- SWR hooks: usePageSpeedConfig, usePageSpeedLatest, usePageSpeedHistory
- GaugeIcon added to sidebar under Infrastructure group