Add data library UI

frontend/src/components/SessionCoverageDots.tsx

@@ -0,0 +1,17 @@
+import { RACE_HUB_DATASETS } from '../lib/coverage'
+import type { DatasetInfo } from '../types'
+
+interface Props {
+  datasets: Record<string, DatasetInfo>
+}
+
+export function SessionCoverageDots({ datasets }: Props) {
+  return (
+    <span className="coverage-dots" aria-hidden="true">
+      {RACE_HUB_DATASETS.map((key) => {
+        const available = datasets[key]?.status === 'available'
+        return <span key={key} className={`coverage-dot ${available ? 'on' : 'off'}`} />
+      })}
+    </span>
+  )
+}