Throw an exception if port is already in use
This branch updates the HttpServer class so that its run method throws an exception if the chosen port is already in use.
Security Notice: GitLab has uncovered a widespread malicious npm supply-chain attack that potentially can destroy user data. All teams are required to audit packages. Further information can be found under the Computer Security Report for November 2025 and the original blog post in https://about.gitlab.com/blog/gitlab-discovers-widespread-npm-supply-chain-attack/
This branch updates the HttpServer class so that its run method throws an exception if the chosen port is already in use.