feat(map): fetch all schools for map view, add reference pin, cap radius at 5mi

- Remove 10-mile radius option; cap backend radius max at 5 miles
- Raise backend page_size max to 500 so map can fetch all schools in one call
- HomeView: when map view is active, fetch all schools within radius
  (page_size=500) instead of showing only the paginated first page;
  falls back to initial SSR schools while loading
- SchoolMap/LeafletMapInner: accept referencePoint prop and render a
  distinctive coral circle pin at the search postcode location

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

nextjs-app/components/LeafletMapInner.tsx

@@ -23,12 +23,14 @@ interface LeafletMapInnerProps {
   schools: School[];
   center: [number, number];
   zoom: number;
+  referencePoint?: [number, number];
   onMarkerClick?: (school: School) => void;
 }
 
-export default function LeafletMapInner({ schools, center, zoom, onMarkerClick }: LeafletMapInnerProps) {
+export default function LeafletMapInner({ schools, center, zoom, referencePoint, onMarkerClick }: LeafletMapInnerProps) {
   const mapRef = useRef<L.Map | null>(null);
   const mapContainerRef = useRef<HTMLDivElement>(null);
+  const refMarkerRef = useRef<L.Marker | null>(null);
 
   useEffect(() => {
     if (!mapContainerRef.current) return;
@@ -43,13 +45,36 @@ export default function LeafletMapInner({ schools, center, zoom, onMarkerClick }
       }).addTo(mapRef.current);
     }
 
-    // Clear existing markers
+    // Clear existing school markers (not the reference pin)
     mapRef.current.eachLayer((layer) => {
-      if (layer instanceof L.Marker) {
+      if (layer instanceof L.Marker && layer !== refMarkerRef.current) {
         mapRef.current!.removeLayer(layer);
       }
     });
 
+    // Add reference pin (search location)
+    if (refMarkerRef.current) {
+      refMarkerRef.current.remove();
+      refMarkerRef.current = null;
+    }
+    if (referencePoint && mapRef.current) {
+      const refIcon = L.divIcon({
+        html: `<div style="
+          width: 20px; height: 20px;
+          background: #e07256;
+          border: 3px solid white;
+          border-radius: 50%;
+          box-shadow: 0 2px 8px rgba(0,0,0,0.35);
+        "></div>`,
+        iconSize: [20, 20],
+        iconAnchor: [10, 10],
+        className: '',
+      });
+      refMarkerRef.current = L.marker(referencePoint, { icon: refIcon, zIndexOffset: 1000 })
+        .addTo(mapRef.current)
+        .bindPopup('<strong>Search location</strong>');
+    }
+
     // Add markers for schools
     schools.forEach((school) => {
       if (school.latitude && school.longitude && mapRef.current) {
@@ -89,7 +114,7 @@ export default function LeafletMapInner({ schools, center, zoom, onMarkerClick }
     return () => {
       // Don't destroy map on every update, just clean markers
     };
-  }, [schools, center, zoom, onMarkerClick]);
+  }, [schools, center, zoom, referencePoint, onMarkerClick]);
 
   // Cleanup map on unmount
   useEffect(() => {