fix: add missing role field to User struct, fix unused variable

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

core/archipelago/src/auth.rs

@@ -120,6 +120,7 @@ impl AuthManager {
             setup_complete: true,
             onboarding_complete,
             totp: None,
+            role: UserRole::default(),
         };
 
         let user_file = self.data_dir.join("user.json");