Add map view for location search results

Implemented split-view map layout for postcode searches:
- List/Map toggle appears when doing location search
- Map view shows interactive map with school markers on left
- Compact school list on right with distance badges, stats, actions
- Mobile responsive: stacks vertically with map on top
- Updated School type to include distance and total_pupils fields

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

nextjs-app/lib/types.ts

@@ -29,6 +29,9 @@ export interface School {
   latitude: number | null;
   longitude: number | null;
 
+  // School context
+  total_pupils?: number | null;
+
   // Latest year metrics (for search/list views)
   rwm_expected_pct?: number | null;
   reading_expected_pct?: number | null;
@@ -41,6 +44,9 @@ export interface School {
   // Trend indicators (for list views)
   prev_rwm_expected_pct?: number | null;
   trend?: 'up' | 'down' | 'stable';
+
+  // Location search fields
+  distance?: number | null;
 }
 
 // ============================================================================