Add list/map view toggle for location search results

When searching by location, users can now toggle between list view
(school cards grid) and a split map view showing:
- Interactive map on left with all school markers
- Scrollable school list on right
- Blue marker for search location, default markers for schools
- Clicking a marker highlights and scrolls to the corresponding card

Mobile responsive with stacked layout on smaller screens.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/app.py

@@ -350,7 +350,7 @@ async def get_schools(
         "page": page,
         "page_size": page_size,
         "total_pages": (total + page_size - 1) // page_size if page_size > 0 else 0,
-        "search_location": {"postcode": postcode, "radius": radius}
+        "search_location": {"postcode": postcode, "radius": radius, "lat": search_coords[0], "lng": search_coords[1]}
         if search_coords
         else None,
     }