fix: Improve API initialization with lazy Supabase client and validation

- Move Supabase/Stripe initialization inside GET/POST handlers for lazy loading
- Add validation for missing environment variables in runtime
- Improve error handling in payment intent creation
- Clean up next.config.js environment variable configuration

This fixes potential build-time failures when environment variables are not available
during static generation.

app/api/aperture/stats/route.ts

@@ -6,17 +6,13 @@ import { createClient } from '@supabase/supabase-js';
  * @returns Statistics for dashboard display
  */
 
-const supabaseUrl = process.env.NEXT_PUBLIC_SUPABASE_URL || 'https://your-project.supabase.co'
-const supabaseServiceKey = process.env.SUPABASE_SERVICE_ROLE_KEY || 'your-service-role-key-here'
-
-if (!supabaseUrl || !supabaseServiceKey) {
-  throw new Error('Missing Supabase environment variables');
-}
-
-const supabase = createClient(supabaseUrl, supabaseServiceKey);
-
 export async function GET() {
   try {
+    const supabaseUrl = process.env.NEXT_PUBLIC_SUPABASE_URL || 'https://your-project.supabase.co'
+    const supabaseServiceKey = process.env.SUPABASE_SERVICE_ROLE_KEY || 'your-service-role-key-here'
+
+    const supabase = createClient(supabaseUrl, supabaseServiceKey);
+
     const now = new Date();
     const todayStart = new Date(now.getFullYear(), now.getMonth(), now.getDate());
     const todayEnd = new Date(todayStart);