fix: add environment variable fallback for Supabase client configuration

shop/lib/supabase/proxy.ts

@@ -13,11 +13,12 @@ export async function updateSession(request: NextRequest) {
     return supabaseResponse;
   }
 
-  // With Fluid compute, don't put this client in a global environment
-  // variable. Always create a new one on each request.
+  const supabaseUrl = process.env.NEXT_PUBLIC_SUPABASE_URL || process.env.SUPABASE_URL;
+  const supabaseAnonKey = process.env.NEXT_PUBLIC_SUPABASE_PUBLISHABLE_KEY || process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY || process.env.SUPABASE_ANON_KEY;
+
   const supabase = createServerClient(
-    process.env.NEXT_PUBLIC_SUPABASE_URL!,
-    process.env.NEXT_PUBLIC_SUPABASE_PUBLISHABLE_KEY!,
+    supabaseUrl!,
+    supabaseAnonKey!,
     {
       cookies: {
         getAll() {