fix: simplify playground navigation - just hide Next button

Previous button stays "Previous" and works the same everywhere.
Only difference in playground: Next button is hidden.

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src/auth.js

@@ -17,12 +17,9 @@ export async function handleOAuthCallback() {
 
   // Check if hash contains OAuth tokens (access_token, error, etc.)
   if (!hash.includes("access_token") && !hash.includes("error_description") && !hash.includes("refresh_token")) {
-    console.log("[Auth] No OAuth tokens in hash");
     return false;
   }
 
-  console.log("[Auth] OAuth callback detected in URL hash");
-
   try {
     const supabaseModule = await import("./supabase.js");
     if (!supabaseModule.isConfigured) {