fix: handle login failure after registration

src/app/register/page.tsx

@@ -32,8 +32,13 @@ export default function RegisterPage() {
       return;
     }
     // Direct inloggen na registratie
-    await signIn("credentials", { username, password, redirect: false });
+    const loginRes = await signIn("credentials", { username, password, redirect: false });
-    router.replace("/");
+    if (loginRes?.error) {
+      // Registratie gelukt maar inloggen mislukt — stuur naar login
+      router.replace("/login");
+    } else {
+      router.replace("/");
+    }
   }
 
   return (