How do I install a plugin on CI or a server?

Use the same email and license key on every machine, given to Composer in the COMPOSER_AUTH environment variable instead of a committed auth.json:

{"http-basic":{"qalainau.privato.pub":{"username":"your-email","password":"your-license-key"}}}

• GitHub Actions: save that JSON as a repository secret named COMPOSER_AUTH, and add env: COMPOSER_AUTH: ${{ secrets.COMPOSER_AUTH }} to the step that runs composer install.
• Ploi, Forge and other servers: put it in the server's environment for the deploy script, or run composer config --auth once on the server as the deploy user.

A Single Project license covers all environments of its project (local, staging/CI and production).