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/SchoolMap.tsx

@@ -28,10 +28,10 @@ interface SchoolMapProps {
   referencePoint?: [number, number];
   onMarkerClick?: (school: School) => void;
   nationalAvgRwm?: number | null;
+  laAverages?: Record<string, number | null>;
 }
 
-export function SchoolMap({ schools, center, zoom = 13, referencePoint, onMarkerClick, nationalAvgRwm: _nationalAvgRwm }: SchoolMapProps) {
-  // TODO: thread _nationalAvgRwm to LeafletMapInner (Task 7)
+export function SchoolMap({ schools, center, zoom = 13, referencePoint, onMarkerClick, nationalAvgRwm, laAverages }: SchoolMapProps) {
   const wrapperRef = useRef<HTMLDivElement>(null);
   const [isFullscreen, setIsFullscreen] = useState(false);
 
@@ -91,6 +91,8 @@ export function SchoolMap({ schools, center, zoom = 13, referencePoint, onMarker
         zoom={zoom}
         referencePoint={referencePoint}
         onMarkerClick={onMarkerClick}
+        nationalAvgRwm={nationalAvgRwm}
+        laAverages={laAverages}
       />
     </div>
   );