This article helped for me Guide to Setting Up Discourse Development Environment - Windows 11
It appears that you should run this:
DISCOURSE_HOSTNAME=localhost UNICORN_LISTENER=localhost:3000 bin/ember-cli -u
it starts:
- rails server
- sidekiq
- ember-cli
And discourse becomes available at localhost:4200
It’s a shame that this is not mentioned in DEVELOPMENT-OSX-NATIVE nor in DEVELOPER-ADVANCED.md