Update Supabase client to use environment variables

src/lib/supabase.ts

@@ -1,3 +1,6 @@
-const supabase = createClient('https://your-project.supabase.co', 'your-anon-key');
+import { createClient } from '@supabase/supabase-js';
 
-export default supabase;
+export const supabase = createClient(
+  process.env.VITE_SUPABASE_URL as string,
+  process.env.VITE_SUPABASE_ANON_KEY as string
+);