feat(map): rebuild popup as mini card with Ofsted badge and headline metric

Replaces the bare Leaflet popup with a mini card showing school name,
3-state Ofsted badge (OEIF grade / ReportCard / pending), phase tag,
headline metric (Att8 for secondary, RWM% for primary) with delta vs
LA/national average, and a styled View Details button. Threads
nationalAvgRwm and laAverages from HomeView → SchoolMap → LeafletMapInner.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

nextjs-app/components/HomeView.tsx

@@ -261,6 +261,7 @@ export function HomeView({ initialSchools, filters, totalSchools }: HomeViewProp
                 referencePoint={initialSchools.location_info?.coordinates}
                 onMarkerClick={setSelectedMapSchool}
                 nationalAvgRwm={nationalAvgRwm}
+                laAverages={laAverages}
               />
             </div>
             <div className={styles.compactList}>