feat: Implement support for prompt=create in the authorization code flow

src/service/users/mod.rs

@@ -245,6 +245,7 @@ impl Service {
 
 			let suffix = &self.services.config.new_user_displayname_suffix;
 			if !suffix.is_empty() {
+				displayname.push(' ');
 				displayname.push_str(suffix);
 			}