Fix: Use correct API base URL for client-side fetches

The compare screen and school search modal were not working because
they were fetching from '/api' directly instead of using the
NEXT_PUBLIC_API_URL environment variable that points to the backend.

Fixed client-side fetch calls in:
- ComparisonView: Fetch comparison data with correct API URL
- SchoolSearchModal: Search schools with correct API URL

This ensures client-side requests go to the FastAPI backend at
the configured URL (e.g., http://localhost:8000/api) rather than
trying to hit non-existent Next.js API routes.

Fixes comparison screen showing no data when schools are selected.

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

nextjs-app/components/ComparisonView.tsx

@@ -55,7 +55,8 @@ export function ComparisonView({
 
     // Fetch comparison data
     if (selectedSchools.length > 0) {
-      fetch(`/api/compare?urns=${urns}`)
+      const apiBaseUrl = process.env.NEXT_PUBLIC_API_URL || '/api';
+      fetch(`${apiBaseUrl}/compare?urns=${urns}`)
         .then((res) => res.json())
         .then((data) => setComparisonData(data.comparison))
         .catch((err) => console.error('Failed to fetch comparison:', err));